: 5000 mile or wait for oil life trigger?



transylvania
03-10-06, 12:43 PM
I just passed 5000 miles but I still have about 60% oil life left. My dealer says to have maintenance now.

Is he right or is he out after the money?

BarryNS
03-10-06, 02:07 PM
Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly, you
must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL SOON message in
the DIC will come on. See DIC Warnings and Messages
on page 3-74. Change your oil as soon as possible
within the next 600 miles (1 000 km). It is possible that,
if you are driving under the best conditions, the oil
life system may not indicate that an oil change is
necessary for over a year. However, your engine oil and
filter must be changed at least once a year and at
this time the system must be reset. Your dealer has
GM-trained service people who will perform this
work using genuine GM parts and reset the system. It is
also important to check your oil regularly and keep it
at the proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.

Cajonkev
03-10-06, 02:22 PM
Well since you have synthetic you should wait unless there is some other condition (Long constant idling, towing, constant high heat/hard driving) effecting your vehicle.

The "official" line for GM as I recall is that you are required to do it within 600 miles of the DIC telling you to, or every 12 months whichever is sooner.

Oil changes are a cash cow for all providers since the recommendations for changes does not match the improvement in oil formulation. Especially for synthetics. Considering your Northstar doesn't just track miles but actually measuresestimates viscosity based on temperature and revs, I'd be smacking that Service Adviser around...:thepan:

My first change occurred at 10k which is right when the DIC told me to. I walked back with the Service Manager during the service and smelled/touched the old oil myself and it was still in great shape.

That's my 2cents worth.

transylvania
03-10-06, 10:35 PM
I have read the manual over and over and although I am a little confused about Maintenance I and II, I posted the question to get a sense of what other owners have been doing. A fool and his money are soon parted and I am no fool.
I will let the oil life information drive my decision on when to go in for service, especially since I have babied this car. I am going this weekend from Santa Barbara to Laguna Beach so that will be the first long range drive for this car.

chevelle
03-11-06, 02:56 AM
Follow the oil life monitor. Period. The dealer is just trying to get the car in for service so as to find other things to try and sell you. The oil life monitor is accurate and the only way to know when to change your oil based on your driving schedule. The dealers and oil change places are loosing money on frequent oil changes because of the oil life monitor so they try to bad mouth it and cause people to not trust it.

Jesda
03-13-06, 10:32 AM
WARNING: UNPOPULAR OPINION

The OLM is a hilariously overengineered joke, but youre running a synthetic oil so you may be good for 7-10k. Depending on how you drive and the number of cold starts per day (I know your climate is pretty mild) you may want to change the filter at every half oil change to be on the safe side.

Until the OLM learns to read and analyze your oil on the fly with the ability to report the level of contaminants and amount of detergents remaining, its just an amusing gimmick.

CIWS
03-13-06, 02:24 PM
WARNING: (another) UNPOPULAR OPINION

I run Synthetic as well and if I have 5000 miles on my oil I'm going to start thinking about getting my oil changed no matter what some damned computer says. Now I don't think you're in a do or die situation yet, but you should consider all things. Is it your desire to keep this car for many years, possibly passed any warranty ? If it's a lease and your going to give it up in three years, then honestly how much do you really care about extending the life of the engine ? If it's a car you may keep then an oil change done regularly can be some pretty "cheap" maintenence. Of course I'm running a V and my engine is ran like a V so it's important for me to keep fresh oil lubing that engine. Do you have the cash (about 75.00 at a stealership) then no sweat. If things are a little tight right now then wait a little bit. Also if you plan on keeping it and don't like the cost of paying someone to change your oil, then buy the stuff and do it yourself. That can be about 30.00 for each change. That's my .02c

mtflight
03-17-06, 09:57 PM
WARNING: UNPOPULAR OPINION

The OLM is a hilariously overengineered joke, but youre running a synthetic oil so you may be good for 7-10k. Depending on how you drive and the number of cold starts per day (I know your climate is pretty mild) you may want to change the filter at every half oil change to be on the safe side.

Until the OLM learns to read and analyze your oil on the fly with the ability to report the level of contaminants and amount of detergents remaining, its just an amusing gimmick.

Your user manual indicates that if you live in a dusty climate you should change your oil more frequently. That's the only other reason to not follow the OLM.

It is one of the most tested "amusing gimmicks." As a matter of fact it takes engine temperature into account on the fly. If you drive it in the cold, and park it before it reaches operating temperature--expect the OLM to indicate a significant drop in oil life left.

If you do a WOT, it drops 1% almost immediately. I've done cross country driving and see the OLM drop as I do these exciting passing maneuvers.

It's okay to express your opinion, because you're entitled to it. But unfortunately you're not entitled to your own set of facts. :thepan:

It is my opinion that others should not opine without first doing some research. Even Honda (aka the Ricer Co.) has now adopted an OLM, possibly purchased the algorithm from GM--that I don't know.

Jesda
03-18-06, 12:29 AM
Sorry, but the only reality is an oil analysis done at a laboratory of a 5000 mile OCI sample versus a sample from following the OLM, showing contaminents and detergents remaining. That will determine what the facts are.

mtflight
03-18-06, 12:53 AM
Sorry, but the only reality is an oil analysis done at a laboratory of a 5000 mile OCI sample versus a sample from following the OLM, showing contaminents and detergents remaining. That will determine what the facts are.

Astonishing perception of the obvious there. :thumbsup:

Not all of us have the time or resources to have our oil analyzed every.... every how many miles do you analyze yours?

There are exceptions to virtually anything. The OLM is designed for most individuals, and is customized on the fly, based on real variables, and tested under a variety of environments both driving and climatologic extremes. It was tested in the way OEM products are, because that's what it is.

It helps the environment--less oil waste, and saves the consumer money (or you can go to a lab for analyses and spend the money there--but if you're so eager to spend it let me give you my Paypal address).

There are forum members here that have used it for the life of their caddies without sign of any sort of engine wear. No signs of trouble yet... as I pointed out other manufacturers are following suit, such as Honda.

I don't particularly think they put it in as a gimmick to "sell cars," it wouldve been cheaper to not put it in at all. But it saves the environment. Still not sure? do your own backyard science testing by taking your oil to a lab, following the OLM--then you can back up your "hilariously overengineered joke" theory with something more objective than your opinion.

Zorb750
03-18-06, 12:55 AM
I just do mine when it tells me to because I use synthetic oil anyway, and not that Castrol swill (I will explain fake synthetics at a later date). It usually works out to around 6000 miles.

mtflight
03-18-06, 01:03 AM
I just do mine when it tells me to because I use synthetic oil anyway, and not that Castrol swill (I will explain fake synthetics at a later date). It usually works out to around 6000 miles.

Lets not start an oil war. Synthetic is superior--no argument there.

But it is particularly superior at temperatures beyond the normal operating temperature of the Northstar and most other car engines out there.

At the normal temperatures, dyno oil works just as well. It's the additives such as zinc (ZDP) that matter--and those deplete just as quickly in synthetic than they do in dyno oil.

I'd rather have synthetic in my engine if it ever overheated. But I would also turn it off and have it towed if it was overheating, so as to not test its limits anyway.

Jesda
03-18-06, 06:48 AM
Synthetic "extended drain" oils are supposed to have more aggressive detergent packages. The question is, how durable is your filter? Some oil analyses have shown Mobil 1 to be viable for as much as 10k in some vehicles, in some driving conditions in friendly climates, but with filter changes every 3-4k and regular topoffs.

If you do end up going a year without changing your oil based on the OLM, DO NOT go a year without checking fluid levels!!!! Just because you aren't electronically instructed to open the hood, doesn't mean you shouldn't.

We will see in time if the latest generation of Northstar engines is as problematic as the last.

El Dobro
03-18-06, 10:34 AM
Since GM put the oil life monitor in there, they'll have to do good by it if there's any problems. Just keep records.

Night Wolf
03-18-06, 10:59 AM
Go by the OLM. It is a far, far better way to judge when to change oil then a simple XXXX amount of miles :).

I go by the oil life monitor on the '93 Coupe. Comes out to be usually 5,000-6,000 miles... I also use Mobil 1 synthetic extended performance 10W-30. With 116k miles on my 4.9 its as clean as a whistle inside :).

Jesda
03-18-06, 06:02 PM
Considering the hell a lot of members here have to go through for warranty coverage and buybacks, I would NOT wait for GM to pick up the tab for a sludged-up motor.

Safe > Sorry.

Keep your filter fresh if you decide to go nuts with your OCI.

mtflight
03-18-06, 06:09 PM
Considering the hell a lot of members here have to go through for warranty coverage and buybacks, I would NOT wait for GM to pick up the tab for a sludged-up motor.

Safe > Sorry.

Keep your filter fresh if you decide to go nuts with your OCI.

Filter is changed at every oil change.... mine run about every 7K miles.

U dont haveto follow the OLI, it's not mandatory; however, it's good enough for the lifetime of your car and it is unlikely you would see any signs of oil related damage at all. Come on, I mean do you really believe that? Sludged up motor? I mean really. How many forum members have that situation? Keep in mind this IS the place where folks come to complain.

Following the OLI is good enough to keep your car healthy, and it's good for the environment.

Sure new fresh oil is better than oil that has seen 5000 miles, but will u see a significant increase in performance from it? No.

Throughout these "Extended" oil changes, we have to top off anyway, refreshing the anti-wear additive packages.

Zorb750
03-18-06, 10:49 PM
Lets not start an oil war. Synthetic is superior--no argument there.

But it is particularly superior at temperatures beyond the normal operating temperature of the Northstar and most other car engines out there.

At the normal temperatures, dyno oil works just as well. It's the additives such as zinc (ZDP) that matter--and those deplete just as quickly in synthetic than they do in dyno oil.

I'd rather have synthetic in my engine if it ever overheated. But I would also turn it off and have it towed if it was overheating, so as to not test its limits anyway.

Right. It still does break down a lot less though at the temp the Northstar does see, starting around 250 degrees F. As far as additives, absolutely correct.

What I mean about fake synthetics is that group 3 base oil does not constitute a synthetic oil. It's still natural, just processed natural oil. That's why Castrol Syntec is garbage. Its thermal breakdown stability is only a little better than regular oil, and nowhere near that of Mobil1 or Redline. Pennzoil's new synthetic is also a hydrocracked group 3 oil, so it's crap too.

Incidentally, the difference with Mobil 1's extended is just that, it's the additives. PAO synthetic oils have matured to the point that the worry is additive depletion, not breakdown. I still don't agree with running 15000 miles on an oil change, I think you would probably have serious additive depletion even with that oil.

Jesda
03-19-06, 03:54 AM
I've taken apart 100k-180k engines that got dino every 5k and ones that got synthetic. The synthetics are always glistening clean, while the dinos show caked-on grime that will take hours to remove. Now picture that grime in your narrow oil passages, with annual oil changes.

If youre leasing your Cadillac, don't bother doing more than what the OLM says. Its not your problem. If you're a 200-300k cross-country driver like me, take better-than-suggested care of your vehicle if it matters to you.

If you buy Castrol Syntec, look for the bottles that say they came from Germany. THOSE are the real synthetics.

mtflight
03-19-06, 12:44 PM
I've taken apart 100k-180k engines that got dino every 5k and ones that got synthetic. The synthetics are always glistening clean, while the dinos show caked-on grime that will take hours to remove. Now picture that grime in your narrow oil passages, with annual oil changes.

If youre leasing your Cadillac, don't bother doing more than what the OLM says. Its not your problem. If you're a 200-300k cross-country driver like me, take better-than-suggested care of your vehicle if it matters to you.

If you buy Castrol Syntec, look for the bottles that say they came from Germany. THOSE are the real synthetics.

You're likely talking about older cars with questionable oil change histories. The viscosity improvers back then were relatively poor quality and the long chain polymers used would break down in high temp areas causing varnish and carbon deposits. Ring belt deposits and stuck rings were common on engines back in the 70/80's.

The current oils rated SL or SM for API performance, use synthetic viscosity improvers and detergents so there is little or no concern over their use in general. This myth about current dino oil vs. synthetic is likely a holdover from the problems of those oils in the past. Ask the forum members that have had their Northstar engines apart--they report none of this nonsense that you claim. :thepan:

Zorb750
03-19-06, 01:53 PM
Interesting about German Syntec. The MSDS for Syntec doesn't differentiate, it's all shown as HC Group 3 oil. I know Castrol makes BMW's "High Performance Synthetic Oil" (its actual title) and it is a PAO formulation (like Mobil1), different from Syntec. Syntec always does badly on the 4 ball test anyway, so I will stick with Mobil.

I have to agree with both Jesda and mtflight about synthetic/natural, old/new oils, though with different things on each. Modern "dino" oils do leave fewer deposits than older ones, but synthetics when burned or evaporated do so cleanly and fairly completely. The "dino" oil does leave residues far more, regardless of if its VI agent is parafin based or synthetic. Now, most of those agents aren't parafin based anymroe, they haven't been in a long time. The only oils with synthetic oil based VI agenrs are sold as such, "synthetic blend". VI agents are otherwise polymer molecules, synthetic in nature, which change in length based on temperature. These molecules are eventually shortened permanently as the oil is used, leading to breakdown in viscousity. This isn't the same as "thermal breakdown" in which the structure of the petroleum itself is altered by heat, but can still be aggrivated by high temperatures. The high dependence on VI agents is the reason 10w40 natural oil is garbage. Synthetic oils use no such VI agents.

Night Wolf
03-19-06, 11:47 PM
Considering the hell a lot of members here have to go through for warranty coverage and buybacks, I would NOT wait for GM to pick up the tab for a sludged-up motor.

Safe > Sorry.

Keep your filter fresh if you decide to go nuts with your OCI.

I've been following the OLM on the Caddy.... comes out to be every 5-6k miles... I change the filter at every oil change... no sooner or later. I use Mobil1 synthetic 10W-30, but this past oil change I used Mobil Delvac 15W-40....

There is not a spec of sludge at all in my 116k mile engine.... the GM OLM is good stuff to go by... it knows far more how much "life" is left in the oil then a random selection of miles driven.

Zorb750
03-20-06, 01:15 AM
Delvac?!?! Your car is not a diesel, Rick.

It's usually best not to drink so much before you work on your car.

Jesda
03-20-06, 05:42 AM
Routine is not random!

GreenMachine
03-20-06, 07:02 PM
figured I chime in here.

The GM oil live indicator is praised by some, hated by others. What I find intresting is that GM uses this system and hasn't recieved any of the types of complaints that I heard Toyota had with sludge build-up. The local news did a huge story about it, those people followed thier toyota oil light and got a dead engine. I've (we've, my father and I) have been following the GM oil life monitor in the 98' Deville and have a strong pulling engine, we use a Kendall Synthetic Blend oil.

Our rule of thumb is, if going on a long trip, get the oil changed beforehand, will be less to think about when getting back, if its been a dirty winter, change it early, and most importantly just look at the oil from time to time, if your oils is starting to get real dark in color then its time to change. Be proactive and check the levels. Usually when the EOLI says under 20% we start to watch it closer and change it.

The trick is remembering to reset it :)

chevelle
03-20-06, 09:19 PM
WARNING: UNPOPULAR OPINION

The OLM is a hilariously overengineered joke, but youre running a synthetic oil so you may be good for 7-10k. Depending on how you drive and the number of cold starts per day (I know your climate is pretty mild) you may want to change the filter at every half oil change to be on the safe side.

Until the OLM learns to read and analyze your oil on the fly with the ability to report the level of contaminants and amount of detergents remaining, its just an amusing gimmick.


Jesda, you are speaking of something you know absolutely NOTHING about. And you are wrong. Please stop spreading misinformation...or maybe you own an oil change franchise and have a motive here....

The GM oil life monitor was thoroughly tested and validated before it was first put into production vehicles back in 1986. In almost 20 years of use there are no reported problems with the system and it's accuracy. It has FAR more credibility than the internet experts like you.

The GM Oil life monitor is calibrated and spec'd specifically for each different GM engine that it is installed on. That is why it tops out at different mileages for different engines and different years. The engine design changes reflect in the allowable oil life for that engine so the oil life monitor is changed and recalibrated accordingly.

Either you are completely ignorant of how the oil life monitor works and the effort put into it....or you own stock in an oil change store that wants people to keep believing in 3000 mile oil changes.

The oil life monitor takes into account ALL the factors that degrade the oil and monitors it on a real time basis and projects the anticipated oil life based on the engine operating schedule todate (since it was reset with fresh oil.) There is absolutely NO other system or method of duplicating the accuracy of this system. Oil sample analysis is "after the fact". If you wait for the sample you may well run past the necessary change interval for your operating conditions.

The GM oil life monitor has been qualified against tens of thousands of actual oil samples over the years to ascertain its accuracy. What you suggest has been done over and over and the oil life monitor has always been right. Even the doubters on BITOG have been convinced it works with the samples people have taken and compared to the oil life monitor. You are barking up the wrong tree saying it doesn't work and that it is a gimmick.

In any case you are making statements that a moderator on the forum should not make since they are completely in error.

Jesda
03-21-06, 03:57 PM
Rudely declaring me "wrong" or "ignorant" does not make it so. A proper OLM would -not- allow annual oil changes! The owner's manual even specifies a change at 12,000 miles in the event that the OLM suggests going further. Liability issue or the limitation of computers over at determining real-world issues?

The OLM has to use operating conditions and base measurements to draw a conclusion -- it does not actually monitor or examine the oil! The -reason- for sending oil to a lab for analysis is to examine the effectiveness of the OLM against a 3-5k OCI.

And yes, I've read our own Bob's arrogantly but informatively written diatribes on the OLM at other forums. He was rightfully banned a while ago, but his posts are still there:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=010523

Now, after reading that and GM's tech bulletins and press releases, I suggest looking into an opposing view. It doesn't matter if your oil lasts 10,000 miles. Open your hood and examine your fluids 4 times a year.

Outside of the Cadillac realm, can you trust your filter for one year? For 8k? 10k? 12k? Are you using Delco, Wix, Champion, Bosch, M1, or are you using Fram? Remember, the OLM can't measure filter life -- it actually doesn't measure anything. It draws conclusions based on conditions. MB's system will ask what type of oil you're using and uses an optical sensor. MB oil capacities are also very high, extending the life of the oil and making contamination less an issue; two plugs per cyl. [Peeing in a lake versus peeing in a puddle.]

3k OCIs are indeed becoming a thing of the past with modern oils in modern engines, but the GM OLM is not the voice of God. Take its measurements into consideration against real-world conditions and fluids and draw your own conclusions.

It would be ideal if we could discuss this issue without you insulting me or accusing me of owning a Jiffy Lube.

chevelle
03-21-06, 10:32 PM
Jesda, you declaring the GM OLM a "hilariously overengineered joke" warrants telling the world that you are wrong. It may be rude but it is fact. If you want to point out what you perceive as weaknesses in the OLM or whatever that is fine but it is not the position of a forum moderator to make statements like that. Some people reading the forum might just think you know something about Cadillacs and the OLM (wrong) since you are a moderator and you should not make statements like that.

You also mention that the poster might be all right with an extended drain interval since he was using "synthetic". That is also an erroneous statement. No automaker recommends extended drain intervals by using synthetic oil and the GM OLM recognizes the same drain interval whether synthetic is used or not. Whether you like it or not, lubrication engineers know that synthetic does nothing for extending drain intervals. Synthetic does have performance advantages. Specifically, it has much slower oxidation rates above 305 degrees F compared to conventional oil. IF that was the reason for drain intervals then synthetic would possibly warrant an extended drain. Trouble is, oxidation is rarely, if ever, the driving force behind drain intervals so synthetic has no practical advantage in that arena. To imply otherwise is simply wrong. It is not my opinion. It is a fact. Read the text books and scientic literature and forget your internet and marketing derived "knowlege" otherwise.

FYI, change intervals are typically driven by acid formation, ZDP depletion, gas and water contamination, etc....things that synthetics offer absolutely no advantage in. Thus, change intervals for synthetics are the same for conventional oil in most all applications. Once again, just facts, not opinion.

You mention comparing used oil life, via oil analysis, to the GM OLM for the real facts. The real facts are that GM has done that for tens of thousands of samples to develop and validate the OLM and in all cases the OLM is actually very conservative. Each new vehicle/engine combination goes thru the same validation process comparing used oil analysis to the OLM model to confirm that it is applicable. How can anyone question whether it works or not??

Did you think GM dreamed up the OLM, put it into cars never used oil analysis to confirm it's accuracy....??? In fact, a battery of used oil samples from various engines at various miles was used in the very beginning to develop the original computer models for oil aging and the model was tested and developed for over 6 years before it even went into production. Since then the model has proven itself in production vehicles for 20 years with no problems.

I am not against people opening their hood and checking their fluids. I am just explaining that the oil life monitor is a useful, well developed means of deciding when to change your oil.

One problem with your blanket advice for 3K or 5K oil change intervals is that in short trip, winter driving that is often TOO LONG. The GM oil life monitor will take short trips and cold starts into account and shorten the oil life accordingly. Too many people assume that the GM OLM just extends oil life excessively. It models oil life for the individual operator of that vehicle. That is the most accurate means of scheduling oil changes. There is no blanket oil change interval that applies to everyone. Hence, the advice to follow the OLM is valid and sound.

The GM oil life monitor is also calibrated to account for the (increased) sump volume of some engines and extends the oil change interval accordingly. Thanks for pointing this out but the GM engineers that develped the OLM figured that out 25 years ago....LOL.

As far as you owning a Jiffy Lube, I was searching for some rational to explain your position and comments. I'm still baffled. Whether it is an oil life sensor or computer model, if the sytem works, why would you try to convince people to not follow the oil life monitor if it is the recommended method of determining oil life by the manufacturer.

Exactly why does 2 plugs in a MB engine help the oil life...???

One of the short comings of the oil life sensors currently available is that they are fouled by some components in engine oil and they can erroneously respond to some of the "marker" elements that oil companies put in their oil. That is one reason that you must specify the type of oil or use a particular type of oil with them. The GM system avoids this alltogether.

I would agree that none of the oil life systems on the market are "perfect". There are short comings with all of them. The engineers that develop them understand the short comings much better than you do and there are safe guards in the systems to account for this. The question is do they work for the customer and perform the service required. They do. Don't knock them.

mtflight
03-21-06, 10:45 PM
Outside of the Cadillac realm, can you trust your filter for one year? For 8k? 10k? 12k? Are you using Delco, Wix, Champion, Bosch, M1, or are you using Fram? Remember, the OLM can't measure filter life -- it actually doesn't measure anything. It draws conclusions based on conditions.

The simple answer here is that the OLM was validated by testing it with the OEM filter specified in the manual. Use a different filter and you're the one doing the testing, and the sole one responsible if something goes awry.

Jesda
03-24-06, 10:46 AM
Its your car. See you at 250k! [I've been there quite a few times.]

FYI: The -best- reason for a synthetic lubricant is the colder pour point. If you live in middle America or New England, you -want- the advantage of well-lubricated cold starts. No reason to have a snow-plowing AWD STS in Michigan if you intend to abuse it with conventional motor oil.

GreenMachine
03-24-06, 11:10 AM
Its your car. See you at 250k! [I've been there quite a few times.]

FYI: The -best- reason for a synthetic lubricant is the colder pour point. If you live in middle America or New England, you -want- the advantage of well-lubricated cold starts. No reason to have a snow-plowing AWD STS in Michigan if you intend to abuse it with conventional motor oil.

arn't they factory filled with mobil 1 synthetic now? That would mean the EOLI is setup for it and validated with that oil in that engine, thats my understanding of the system anyway.

chevelle
03-24-06, 11:44 AM
The RWD and supercharged Northstars are factory filled with Mobil 1. There are two reasons:

One being that the oil temp can exceed 305 during "performance" driving...i.e..extended autobahn and track work. For those rare situations, rather than saddle every vehicle with an extensive oil cooler system, the use of the synthetic oil allows the oil temp to exceed 305 F without excessive oxidation.

Secondly, the VVT system in the RWD engines uses the engine oil pressure to actuate the VVT mechanism via a PCM controlled spool valve. The more linear viscosity characteristics of the synthetic oil when cold allow earlier operation of the VVT system and more precise control. This is strictly a hydraulic circuit advantage for the hydraulic control of the VVT and not a lubrication issue.

The OLM is calibrated for those engines, yes, but the oil change intervals is no different than for the similar transverse engines that are spec'd for conventional oil. There is nothing with the synthetics that is recognized to increase the oil change intervals.

The 12,500 mile maximum oil change interval is achieved via the incorporation of roller followers at the camshaft compared to the direct acting flat tappets (rubbing elements) in the Northstars prior to 2000 model year. The roller tappets deplete the oil less and are far more tolerant of depleted oil allowing much longer drain intervals.

Jesda, there are now quite a few 2000 and later FWD Devilles with Northstar engines in livery service around Detroit that are routinely run the maximum oil change intervals per the OLM (and beyond) and they have WELL over 250K on all of them.....seen em my self.

Again, since 99% of the oil changes are mandated for contamination and ZDP depletion (NOT oil oxidation) the use of synthetics , whether chosen by the customer or spec'd by the manufacturer, has absolutely no bearing on the maximum oil change intervals. NONE.

It is true that the sythetics have colder pour points. If you were regularily starting your engine in temps of -40 and BELOW I would consider synthetic oil an advantage. Engines are routinely tested under very harsh cold start conditions down to -40 including extreme RPM runup on startup. They funtion perfectly fine with conventional oil. I have personally started a veryt large number of engines at -40 using conventional oil and driven them at WOT immediately after startup with no ill affects on the engine. Funny how people managed to start and run engines at well below -40 for ages before synthetic oil came along to "save" them....LOL. The temperatures in the continental US would rarely if ever give an advantage to synthetic oil for coldstarts. On extremely cold days (like -20F and below) it might give a slight advantage for cranking speed but the lube system could care less.

The idea of "pour points" affecting the lubrication system and the life of the engine is dramatically overblown by the synthetic oil marketiers....for the purpose of selling their products. It is true that the conventional oil is very thick/viscous at cold temps but that has a plus side. There is also a lot of residual oil trapped in the bearings and at wear points and THAT oil is also very viscous. So, it has tremendous load bearing capabilities and it will take a lot of force and/or time to squeeze it out of the load bearing points..i.e..the load interface or the bearing shell. That means that any perceived delay in pumping the cold oil from the sump is more than offset by the extra capacity the bearing has from the cold residual oil in it. If it didn't work this way the engine would self destruct pretty quickly on cold starts if it really wasn't getting any oil as the synthetic oil marketiers would have you believe.

If you take an engine fillled with conventional oil and start it after an overnight cold soak at decreasingly lower and lower temperatures, rev it to 5000 RPM immediately after startup and monitor the oil pressure you will find that the oil pressure will go higher and higher as the temperatures go colder and colder. This is true down to about -20F/-25F. Below that point (depending on the engine) the oil pressure maximums will start to drop off. This is due to the oil getting harder and harder to pump and causing the oil pickup to "starve" and cavitate. Sound bad...??? Actually, it is not. This helps limit cold oil pressure so that the filter and seals do not blow out. If this didn't happen the oil pressure could easily go up to 200 PSI or more where it normally maxes out at about 100/120 PSI. There is actually a good side to the oil system starting to "starve" as the syn marketiers would have you agonizing over....LOL.

Trust me. Millions and millions of engines have been starting for ages in winter weather with conventional oil and they live fine. For 250K even. Those same livery devilles get cold started each morning in Michigan winters and they live fine on conventional oil. The idea of an engine failing or not delivering high miles due to lack of use of synthetic is ludicrous.

auroradude
03-24-06, 02:59 PM
Haha, you guys. I change my oil (regular, castrol GTX high mileage 10w30) every 3500-4k miles. I dont even look at the oil life display, just the oil pressure as thats more important to me. Personally I find $25-$30 every 4 or 5 months pocket change and WORTH IT for a $7,000+ motor. It's not worth it to skimp like my dad used to on $15,000 jag AJ-V8 engines doing oil changes every 10k miles etc before i straightened his ass out. I would do 5k miles on REGULAR OIL at the absolute max...period. Synthetic Mobil 1 i would def do 10k-12k miles as I've seen oil analysis thatp prove there is plenty of life left even. I'd rather take the much safer route than end up regretting for the next 10 years that I wasted $7k on a car that i could end up smashing someday.

I wish i could use synthetic in my motor, but the seals are shot.

mtflight
03-24-06, 03:38 PM
Haha, you guys. I change my oil every 3500-4k miles. I dont even look at the oil life display... I would do 5k miles on REGULAR OIL at the absolute max...period. Synthetic Mobil 1 i would def do 10k-12k miles as I've seen oil analysis thatp prove there is plenty of life left even...I wish i could use synthetic in my motor, but the seals are shot.

Auroradude, no offense, but I refuse to believe you actually read the contents of the thread prior to posting your reply. :bighead:

Ranger
03-24-06, 08:08 PM
It's not worth it to skimp like my dad used to on $15,000 jag AJ-V8 engines doing oil changes every 10k miles etc before i straightened his ass out.
"When I was 17 I couldn't believe how stupid my father was. When I was 22, I was amazed at how much he'd learned in 5 short years".

mtflight
03-24-06, 08:20 PM
"When I was 17 I couldn't believe how stupid my father was. When I was 22, I was amazed at how much he'd learned in 5 short years".

LOL :histeric:

auroradude
03-25-06, 01:04 AM
Heh, I read the whole thread before thinking about posting :bigroll: All I can say is I wont have any oil related failures or sludge buildup. Cheers

davesdeville
03-25-06, 04:54 AM
Neither will I. I use dino oil, and *gasp* regular gasoline! :bighead: My car is not going to explode.

1993 eldorado green1
03-25-06, 01:28 PM
Rudely declaring me "wrong" or "ignorant" does not make it so. A proper OLM would -not- allow annual oil changes! The owner's manual even specifies a change at 12,000 miles in the event that the OLM suggests going further. Liability issue or the limitation of computers over at determining real-world issues?

The OLM has to use operating conditions and base measurements to draw a conclusion -- it does not actually monitor or examine the oil! The -reason- for sending oil to a lab for analysis is to examine the effectiveness of the OLM against a 3-5k OCI.

And yes, I've read our own Bob's arrogantly but informatively written diatribes on the OLM at other forums. He was rightfully banned a while ago, but his posts are still there:
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=1;t=010523

Now, after reading that and GM's tech bulletins and press releases, I suggest looking into an opposing view. It doesn't matter if your oil lasts 10,000 miles. Open your hood and examine your fluids 4 times a year.

Outside of the Cadillac realm, can you trust your filter for one year? For 8k? 10k? 12k? Are you using Delco, Wix, Champion, Bosch, M1, or are you using Fram? Remember, the OLM can't measure filter life -- it actually doesn't measure anything. It draws conclusions based on conditions. MB's system will ask what type of oil you're using and uses an optical sensor. MB oil capacities are also very high, extending the life of the oil and making contamination less an issue; two plugs per cyl. [Peeing in a lake versus peeing in a puddle.]

3k OCIs are indeed becoming a thing of the past with modern oils in modern engines, but the GM OLM is not the voice of God. Take its measurements into consideration against real-world conditions and fluids and draw your own conclusions.

It would be ideal if we could discuss this issue without you insulting me or accusing me of owning a Jiffy Lube.



do i dare ask where bbob went? i see someone else here has his name and post record but he is gone. what happened?

mtflight
03-25-06, 02:06 PM
Heh, I read the whole thread before thinking about posting :bigroll: All I can say is I wont have any oil related failures or sludge buildup. Cheers

Good to hear that.

I just noticed on your avatar that you have a K&N Intake. I bet your car is really cool and it makes a nice sound while it sucks up dirt in the egine (come to think of it, more dirt in th engine merits your early oil changes). http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/68040-k-n-intake-i-want-one.html

IF you have the cone, then even better--I hear that it's supposed to make a cool sound when it hydrolocks, but if you avoid water then it smells really cool while the PCM slowly cooks under the hood (unless you have the older design with the PCM in the passenger compartment).

Either way, you make very educated decisions. Sooooo cool :cool2:

Hey would you like to purchase a bridge? I have the Brooklyn bridge for sale, I'll give it to you for cheap :thumbsup:

mtflight
03-25-06, 02:12 PM
do i dare ask where bbob went? i see someone else here has his name and post record but he is gone. what happened?

Jesda made it sound like he was kicked out for being arrogant which is complete BS. That Bobistheoilguy forum, is owned and operated/moderated by a dealer of Amsoil pyramid oil, "God's gift to the earth."

Someone there probably did not like all the facts being presented which discredited Amsoil's claim to longer drain intervals. They could not back up their statements with any facts, so the easy thing to do for them was to pull the plug and ban him. With Bbob out of the picture there, they could resume their BS about longer drain intervals and how Amsoil is the best oil bar none. They find all these mostly impractical and irrelevant tests and post the ones where Amsoil performs better than the rest to somehow fanangle to back up their claims.

1993 eldorado green1
03-25-06, 03:53 PM
Jesda made it sound like he was kicked out for being arrogant which is complete BS. That Bobistheoilguy forum, is owned and operated/moderated by a dealer of Amsoil pyramid oil, "God's gift to the earth."

Someone there probably did not like all the facts being presented which discredited Amsoil's claim to longer drain intervals. They could not back up their statements with any facts, so the easy thing to do for them was to pull the plug and ban him. With Bbob out of the picture there, they could resume their BS about longer drain intervals and how Amsoil is the best oil bar none. They find all these mostly impractical and irrelevant tests and post the ones where Amsoil performs better than the rest to somehow fanangle to back up their claims.

i ment here, bbob used to be on this site back in 04, why did he leave here? he claimed he was 1 of the engineers who helped design this motor if i remember correctly..

mtflight
03-25-06, 04:22 PM
i ment here, bbob used to be on this site back in 04, why did he leave here? he claimed he was 1 of the engineers who helped design this motor if i remember correctly..

Probably personal reasons--no big scoop or anything. It's his business, so why speculate about it.

dkozloski
03-25-06, 06:07 PM
Bbob got in trouble for giving advice out of official channels. Owners were confronting the factory excuse makers with the real facts and they didn't like looking foolish.
..........
Modern oils and modern engines are both so good that there are very few owners that have ever experienced a lubrication failure. I've seen engines that have NEVER had the oil changed that ran just fine for TWENTY YEARS. I've seen engines that were run successfully with less than a quart of tar black oil left. The beauty of this topic of argument is that there is such a wealth of variables that you can get just about any results you like using any reasoning no matter how flawed. If you like what you're doing, be content with your superior position and bad mouth the other guy to your hearts content. It's just like arguing religion or politics. Only a liberal Democrat would think of ignoring the OLM. Anybody that changes oil on fixed intervals must sleep in his underwear. Flames forever.LOL

GreenMachine
03-26-06, 06:34 AM
Bbob got in trouble for giving advice out of official channels. Owners were confronting the factory excuse makers with the real facts and they didn't like looking foolish.
..........
Modern oils and modern engines are both so good that there are very few owners that have ever experienced a lubrication failure. I've seen engines that have NEVER had the oil changed that ran just fine for TWENTY YEARS.

now thats an engine that I want! Doing that too an engine either indicates it was rarely used and if it was used alot its like playing russian rullet evertime you start it. That just sound funny to me :)

The only true way to know when to change the oil is as the manual says, go by the EOLI and change sooner if dusty/dirty conditions. Question is, how sooner?

Well check your oil, look at it, does it look like its dirty? Have gunk in it? Then change it. If its still clear at 3000, 5000, 7500 no need to change it. Oil gets dirty far faster than it actually loses its lubricant properties. This topic always get beat to death, and honestly if you feel you need to change 3months/3000 then so be it, but plenty of people seem to be doing fine going by the EOLI and checking the oil's appearance.

I believe the manual says to check fluid levels at every fuel fill or once a month, if you do that you'll not only catch low fluids more often, but be able to keep close eye on the conditions of the fluids.

It still remains my impression from the tech's that I have talked to that the EOLI is designed differant for each engine and tested with that engine and the factory fill engine oil. In the case where you put "better" oil in than what was factory filled in some cases you possibly could go over what the EOLI says. Like my 98' for example, factory filled with standard dino oil, but its gets a synthetic blend and runs great going by the EOLI and doesn't drink oil like some northstars.

Guess its all about what you feel comfortable with.

El Dobro
03-26-06, 07:14 AM
bbob is still here in spirit.

Ranger
03-26-06, 10:49 AM
bbob is still here in spirit.
:thumbsup:

dkozloski
03-26-06, 01:29 PM
The worst abuse I ever saw of an engine was an aircraft that threw a rod on approach to landing. When I received the thing for failure analysis there was a fist size hole in the top of the crankcase with a connecting rod sticking through. There was NO oil on the outside of the engine which indicated there was very little inside and none of what was left had been lost with the failure. I very carefully captured all remaining oil as the engine was disassemblied. The total was about 1 1/2 cups of the blackest, burned residue I ever saw. The pilot/owner was totally ignorant of the rate at which his engine had been consuming oil and considered level checks to be a nuisance. The good Lord protects fools and drunks.

auroradude
03-26-06, 02:30 PM
Yeah to the guy above reminds me of someone that changes it once a year regardless of mileage (even if its 25k a year). I cant picture him for some reason. My mom once ran a 2000 exploder 20k without an oil change. She took it in at 5k for the first one then simply forgot about the rest. It ran sooooo bad, whined like you wouldnt believe and it got about 6mpg (V8 but still, it shouldve been like 16). Most were short trips too. I wouldve liked to have seen what that motor looked like inside.

Night Wolf
03-26-06, 03:34 PM
Delvac?!?! Your car is not a diesel, Rick.

It's usually best not to drink so much before you work on your car.

Read up a bit....

JohnnyO
03-29-06, 07:32 PM
We ran Mobil 1 in my father's '04 DeVille (which does not call for Mobil 1) until the OLM was down to 4% and it had 11,200 miles on the oil. No oil added, no filter change. What the heck, it's leased. Sent some used oil to Blackstone just for kicks and the lab results showed it was fine. You can change it more often if you want, it's your money. A used oil analysis is the only way to know for sure. Thing to remember too is that a N* holds 7.5 quarts, so that's 50% more than the average car holds and the oil won't wear out as fast.

www.blackstone-labs.com

Zorb750
04-01-06, 09:07 AM
Read up a bit....

Bah. The point of Delvac is that it can handle the acids from a Diesel engine better.

Northstar333
04-01-06, 05:12 PM
The Guru said to follow the OLM so that's good enough for me.

If someone tells me different then I know they are misinformed.

dkozloski
04-02-06, 05:31 PM
If you consider all the margins that the engineers for GM and the oil companies have figured in for themselves, the company, the wife and kids, and the landlord just about anything you want to do will work. This is not an area where critical hairsplitting and flypoop sorting is required.

cl1986
04-02-06, 06:03 PM
I just went some 8000 miles on mine, the monitor said about 3% life left. I will go by this monitor as it knows better than i do....

It drained out just like the color it was poured in.....as always on the alluminum engines even my 86 deville with the ht4100, the oil always looked new when i changed it.....

As far as the guy with the contaminents being introduced in the oil study, where they INTRODUCING contaminents themselves??using crappy gas?? they dont tell u that stuff...

I did a couple trips to CO and WY is how i got the 8000 miles before the monitor said to change it, makes sense i got some 25 MPG so compared to 19mpg in town a huge amount of gas difference so less contaminets are introduced when your getting 25 mpg....ever think of that??

I think the monitor knows more than u do....

Plus, people have been following this monitor and getting over 300k miles out of the engine with honing marks still visible on the cylinder walls. No need for sythetics here......

AlBundy
04-02-06, 08:10 PM
I agree I'm getting 5k before the OLM tells me to change it and your right the used oil seems to be fine.