: Question about the oil life monitor....



Night Wolf
06-17-03, 01:36 PM
I have a question, in my '93 DeVille (4.9) it has an oil life monitor, but while reading in the manaul, it says to get ready to do your next oil change whent he monitor reaches 10% which is about 7500 miles....

....7500 miles? isn't that high?

So my question is, should I pay any attention to the oil life monitor? or just ignor it...... it seems to me like when it was put in, it was setup for high intervals....maybe so it wouldn't cost as much for oil changes?

I ask becuase I will proablly be changing the oil on my car today, it has 80k miles.... and I am undecided if I should switch the synthetic or not, I am trying to read older threads about it, seems like it is a 50/50.... some say it's not worth the money, others say if you want the engine to last into the higher miles, then it is very worth it...

....only experience I have is, my father has always used synthetics in his '88 Fiero Formula (2.8 V6) he bought it with something like 50k miles, and it now has 170k miles, and although lost alittle power due to age, runs very, very well, and oil pressure is always high.

On the other hand, Richie (moms boyfriend) uses regualr oil in both his Caddy and my mothers (he has an '87 my mom has an '89- both Broughams) and both have the Olds 307..... he dson't think it is worth changing the oil every 3k miles, says it just comes up too fast, so he does it every 5k, plus he said it is more easy to keep track by the miles...... he bought his car with 80 or 90k miles, and now has almost 170k miles, runs it every day, and there are no problems at all.... my mothers car was bought around 80k miles too, and now has about 140k miles, besides a few over heats, it has been a good engine too.

So I was just asking, is the oil life meter worth looking at? and I don't want to start a big debate....but do you guys think that switching to synth. on a 4.9 with 80k miles is worth it?

I have heard 2 things about switching to sythn on cars with more miles..... if you have been using regualr oil, and switch to synth. may break down the deposits left by the regualr oil, which can cause clogging.... and synth tends to leak more easy, there are no leaks on my engine right now, so I don't know if it will start leaking with synth.

BTW the temp around here usually is between 20-100 (F) I am probally going to be using the Caddy this winter, but if it is really bad outside, I wouldn't (only would be going to school and work, so if it's bad out, no school and I'll call in and say I can't make it to work)

Sorry for the long post, any help is great though. Thanks

elwesso
06-18-03, 11:09 PM
Dont waste the money on synth......... It may not be a bad idea to run it in the worst of winter (when its really friggen cold)...... but it shouldnt be a problem if you change it at 3000 anyway.....

Synth does not clean a dirty engine, but it will leave a clean engine cleaner than regular.....

Oil life monitor--- IMO a great way for GMs cars to last a shorter period of time so that you will have to buy new ones sooner, and a way to make it seem like their cars are maintenance free at the same time!!!! Its a good thing to go by, but I wont go past 3500 between changes, and by 3500 miles I am probably getting bored so it will give me something to do.......

Night Wolf
06-19-03, 12:44 AM
Well, I switched to Mobile 1 synthetic today, I figured I have heard good things about it, and it's my gift to my car, not like I do it once a month, but I can think of many ways that I spent/wasted the money on other stupid things. I want to see how this goes, and check the level/valve covers once I start driving, and if I don't seen any leaks etc... I'll keep using the synth..... I have first ahdn seen cars that have 170k mile+ that have had synth and regular oil most of it's life.... but I figured what the hell.

in the manaul, it says the oil life monitor will say to change oil soon (when down to 10%) anywhere from 3000-7500miles, it monitors engine rpm, temp, driving conditons etc.. and tells you, plus at any time I can push the buttons and get a % of how good it is, so once i start driving, I will take note with how many mile si put ont the car and what the monitor is at.

Ralph
06-19-03, 01:33 AM
Panther, what you said made me think of another question, ie. can the oil-life monitor sense the difference between dead dinosaur oil and syn.? and will it change the length of time required between changes?

Anyway, I have used Mobil 1 and dino oil in all my cars and they are supposed to be interchangeable (it says on the bottle) and I have had no problems. I did stop using it on my 1980 Pontiac a few years ago because it has 245,000 kms and it started to leak a little from the valve covers. When the pcv valve (change yours often!) in my 1991 Mercury froze up and I had to get all 4 new oil seals, well after that I used Mobil 1 and it never leaked, probably because the seals were new. I think that with higher mileage, leaking can be a gamble. Once in a while, get a good flashlight and in a dark area like a garage, etc. take a look around the valve cover gaskets and you will know to continue using synthetic or not if you see any wetness from oil in that area. :banghead2

elwesso
06-19-03, 04:40 PM
The oil life monitor has know way of knowing the type or condition of the oil....... It monitors the factors that cause oil to last longer/shorter..... it wont say change oil soon when it lubriation properties are not suffecient by it having some sort of sensor testing it...... it does it by studying the conditions the engine has been running at to GUESS the condition of the oil........

Thats why (if i had it) i wouldnt use it!! Relying on technology has cost me too many times.......

Ralph
06-20-03, 02:04 AM
The oil life monitor has know way of knowing the type or condition of the oil....... It monitors the factors that cause oil to last longer/shorter..... it wont say change oil soon when it lubriation properties are not suffecient by it having some sort of sensor testing it...... it does it by studying the conditions the engine has been running at to GUESS the condition of the oil........

Thats why (if i had it) i wouldnt use it!! Relying on technology has cost me too many times.......

True enough, I monitor the mileage, and do it every 3500 to 4000kms. Thats around 2500miles, I think. I am curious to see what the oil life monitor will say in percentage when I get there.

elwesso
06-20-03, 07:36 PM
Depending on how you drove the car.... It could be anywhere from 10% (rec. change time) to 30%.....

Liseckas
07-09-03, 08:46 PM
I agree to not rely on technology. The best bet is to do like everyone recommends, change your oil and filter at every 3000 miles and you won't go wrong. I have little faith in the current Cadillac "technology".

elwesso
07-10-03, 12:39 AM
If it was something expensive, i may go for it, but an oil change costs like 20 at jiffy lube, Im sure you can spare that every 3000 miles........ Remember, you didnt buy a caddy to wimp out on maintenance...... :)

MMNineInchNails
07-10-03, 01:15 AM
Or you could change your own oil

Liseckas
07-10-03, 12:30 PM
If it was something expensive, i may go for it, but an oil change costs like 20 at jiffy lube, Im sure you can spare that every 3000 miles........ Remember, you didnt buy a caddy to wimp out on maintenance...... :)

Jiffy Lube??? Now you're really asking for trouble. I've heard too many first hand horror stories about them, from not tightening oil pan plugs, not refilling with oil, putting the wrong oil in transmissions(yes, they service transmissions). I would get rid of my cars and ride a bike if didn't have another choice.

elwesso
07-10-03, 09:52 PM
I was just using that as an example........ Most oil changes at reputible places dont cost more than 25, and aybe about 10-15 if you do it yourself (which is more fun)........

MMNineInchNails
07-10-03, 09:56 PM
yep, $1.89 per quart (4 quarts equal $7.56 + tax) and a $2 someodd for a filter.

Liseckas
07-10-03, 10:14 PM
I was just using that as an example........ Most oil changes at reputible places dont cost more than 25, and aybe about 10-15 if you do it yourself (which is more fun)........

Yeah, you just gotta love hot oil oozing down your arm and into your armpit when changing your oil while lying on your back on oil soaked gravely ground.
Whats even better is reaching for a beer while lying on your back and instead grabbing the old oil filled filter and getting a big delicious swig of the black oily stuff.:vomit:YUM!

MMNineInchNails
07-10-03, 10:16 PM
How would hot oil get on you? That's why you drain it into an oil pan before taking off the filter. that way, when you take off the filter, the oil doesn't shoot out everywhere. Who tought you how to change oil?

Liseckas
07-10-03, 10:22 PM
How would hot oil get on you? That's why you drain it into an oil pan before taking off the filter. that way, when you take off the filter, the oil doesn't shoot out everywhere. Who tought you how to change oil?

Oh that happens when you unscrew the drain plug. Who ever heard of not getting your hands dirty when you do something yourself. Beer taught me how to change oil. Didn't ya know it made "Bud wiser".

"...yep, $1.89 per quart (4 quarts equal $7.56 + tax) and a $2 someodd for a filter..."
Hey are you always a quart low?

MMNineInchNails
07-10-03, 10:29 PM
Nope, are you? Drain plug is downward, don't put your finger in the way of the oil.

elwesso
07-10-03, 10:30 PM
But usually you need to factor in more for a better filter and better oil...... The good stuff isnt 1.89/qt....... and a good filter isnt 2.00.....

MMNineInchNails
07-10-03, 10:32 PM
Castrol GTX Drive Hard is pretty good for $1.89. What kind of oil do you put in your car?

Liseckas
07-10-03, 10:33 PM
Nope, are you? Drain plug is downward, don't put your finger in the way of the oil.

Right now I'm down about a fifth. A fifth of JD that is....

Liseckas
07-10-03, 10:40 PM
Castrol GTX Drive Hard is pretty good for $1.89. What kind of oil do you put in your car?

Chevron Delo 400, I buy it by the case like everything else.

elwesso
07-10-03, 11:02 PM
I use valvoline products, next change im gonna put in valvoline maxlife, and a really good filter (maybe a Fram)......I am going to run mobil 1 synthetic ATF, valvoline synpower brake fluid, and mobil 1 ATF for the PS fluid....... Believe it or not, thats what it says to use in the FSM!!!

MMNineInchNails
07-10-03, 11:05 PM
What's an FSM? are you talking about atf in the power steering? Yeah, that's what you always use. Frams are good filters and they are geniouses with their suregrip thing. Brake fluid doesn't really matter, it's all the same, unless it's a differen't DOT.

elwesso
07-10-03, 11:19 PM
FSM= (factory service manual)......

And all brake fluid isnt created equal..... I would rather spend a few extra dollars on the good stuff than a 500 ABS unit!!!

MMNineInchNails
07-10-03, 11:24 PM
i see..........

banstyle
07-11-03, 06:15 AM
Or, just get yourself this bad-ass Fram Suredrain thingy. It replaces your oildrain plug with a hipressure-loaded spring valve. You screw on this adapter, attached to a hose, and it opens the valve and drains your oil through the tube. When your done, unscrew it and then put the cap on. You can drain oil into anything like milk jugs or soda bottles. I don't work for these guys, but it was too bad-ass not to share.

I haven't installed it yet on my car, but it looks and feels durable, and the cap that covers the valve seals real tight, so I dont think you really have to worry about dumping oil all over. I'm going to install it for my Caddie here next oil change.

Check out some details right here. click! (http://shop.store.yahoo.com/rodi/frasdseries.html)

Oh yeah.. you can get this at the local shop. I know AutoZone carries it.

MMNineInchNails
07-11-03, 12:37 PM
Yeah, but what happens when you run out of space to put the old oil in your milk jug? Does it shoot out, or can you turn the oil coming out of it off like a faucet?

elwesso
07-11-03, 02:16 PM
Having the hot oil run down your arm is part of changing the oil...... if its not there, it would just be ruining the affect...... Besides, if i wanted something like that, i could just get one of those pumps you stick through the dipstick hose.....

Night Wolf
07-12-03, 10:14 PM
I used Mobil 1 synthetic, which is $4.78 or so a quart, so $5 x 6 = $30 + $3 or $4 for AC Delco filter = an oil change for me is about $35

But I dunno if I should change my oil every 3k, I was thinking 4k or even 5k...... I dunno, Richie (moms boyfriend as of 15 years) has a '87 Brougham, with the Olds 307, it now has 173k miles, he bought it with 70k, and he uses normal oil (no synthetic) and changes the oil every 5k miles, he even has a small trailer that he hauls around sometimes, the engine dosn't brun, or leak any oil. runs great, still has nice power (whatever power the 307 had) and everything, he said it dosn't pay to change it every 3k and 5k is more easy to remember on the odo......so far my moms car ('89 Brougham, 307) he has done the same.

I don't know if I would go every 5k, maybe 4 or so, I dunno I'll have to see, but with synthetic, aren't you supposed to be able to go longer or something?

elwesso
07-12-03, 10:21 PM
I would rather pay less for regular oil than pay more for synthetic and HOPE it lasts an extra 2000 miles!

MMNineInchNails
07-13-03, 12:30 AM
That's why Castrol GTX owns.

steelerfan
07-14-03, 09:14 PM
Personally I think changing oil every 3000 miles is excessive and a waste of oil and just works to deplete a natural resource faster. Life of modern oils should be great for 5000 no sweat. To be honest I've never had a car where it had problems due to 5K oil change frequency. The most common problem with having 200,000 to 300,000 mile engines with modern computerized cars will be all the peripherial problems with starters, alternators, fuel systems and electronic modules.

With todays cars it is going to be the electronics that will be problems. Cars driven with high miles in a few years won't have the electronics issues as bad since corrosion and other factors won't be a major factor. But cars that aren't driven regulary and sit for periods of times will have issues over the years with the electronics. What is going to happen 15 years from now when the memory chips containing all the information for cars are not produced by manufactures and they have reliability issues.

Most computer chips have only a 1-2 year life before they are obsolete and semi conductor manufactures quit making this part. I know this because I work in Semiconductor business as quality engineer to determine device life expectancies. What really kills electronics modules is time, On/Off cycles, temperature extremes, moisture. These devices won't be easy to reproduce in future like making bumpers, fenders, intake manifolds etc.

Auto manufactures have these parts made for the initial run of cars plus spares for repair. Restoring new computerized cars 10 15 years are going to be a nightmare and it won't be due to the wear and tear on engine parts due to oil change frequency.

So, I will continue with 5K intervals. On the same note though, some engines such as the Toyota motor in camry's, Siena's and Some lexus models have demonstrate a definite issue with oil life and engine failure and on my Sienna it gets the oil change every 3k. But this is the exception rather than role with oil life expectancy.

elwesso
07-14-03, 11:56 PM
Well, to each their own, but im going to go ahead and change it every 3k......

And.... Why do you think we RECYCLE oil???

Night Wolf
07-15-03, 09:08 PM
well, the thing with the 3k stuff, that came out in the 60s and 70's, when the oil wasn't as good quality, even todays cheap and non-synthetic oil is far better then what was around then, so if you have a oil that is better then the yesterdays, then the oil change interval should also be increased.

thu
08-03-03, 03:04 AM
Panther,

I'm looking at the Factory Service Manual (FSM) right now for 1992/1993 De Ville/Fleetwood/Sixty Special. It says on page 0B-3:

Begin Quote from FSM:

All Cadillacs are equipped with and Engine Oil Life Index (EOLI). It uses information received from the Powertrain Control Module to calculate the percentage of oil life remaining at any time. The information that is used to calculate the percentage is:

- Miles driven since last reset.
- Coolant temperature.
- Engine revolutions.
- Vehicle speed.

The oil change intervals determined by the EOLI will usually fall at, or between, the two recommended alternative intervals of 3,000 miles and 7,500 miles, but could be shorter than 3,000 miles under some very severe driving conditions...... If the EOLI does not indicate the need for an oil change after 7,500 miles or one year, or if the EOLI display fails to appear, the oil should be changed and the EOLI system should be serviced.

The EOLI will not detect excessively dusty conditions or engine malfunctions which may affect the oil.....

Also, the EOLI does not measure the oil level....

End of Quote from FSM.

One of the things that determines when the "Change Oil Soon" light comes on is when the number of crankshaft revolutions has reached 18 million since the last reset. On page 8D-40 of the FSM (under Computer System Diagnosis), it says:

Begin quote from FSM:

The BCM monitors the odometer and engine revolutions to determine when the "Change Oil Soon" telltale should be illuminated. When the odometer reaches a count of 7000 miles or when the engine has made approximately 18 million revolutions, the BCM will complete the path to ground for [ the Change Oil Soon lamp ].

End quote from FSM.

If you've read carefully, you'll see that the latter section in the FSM makes no mention of vehicle speed or coolant temperature that the former section does.

I normally change it at about 5,000 miles or so. I use Mobil 1. Nice thing about the Change Oil Soon light is that if I forget, it will remind me.

I think putting my baby (1993 DeVille) on synthetic motor oil since new is mostly responsible for allowing my engine to go 248k miles. On my 1985 DeVille, I switched from dino to syn at about 40k. It went to 238k. If the interval between changes gets a little long, I don't get too excited about it. If I had dino oil in there, that would be a different story.

The oil starts to turns dark at about 2,000 or 2,500 miles. When it comes out at 5,000 miles, it's still clean (no grit or sludge) and feels slippery like new oil out of the bottle. The dipstick stays completely clean, no sludge.

Regarding switching an engine that has a lot of use from dino to syn.....instead of switching to syn, how about just changing the oil more often? Dino is so cheap compared to syn that even if you changed oil three times more often, you'd still come out ahead moneywise. However, that means you have to do the job more often and that would be a drag. If you really still want to switch to syn, I hear that syn oil can clean out a "dino oil" engine to a certain extent and thus the engine may start to leak where the sludge gets washed out. I've only heard (never seen) this and wonder if it's largely a rumor. If you try that and the engine does leak, then maybe it's time for you to tighten bolts, replace gaskets, hoses, etc. I doubt that any leaks will be major. I think the best candidate for switching from dino to syn is an engine that has been properly maintained (e.g. oil changes every 3,000). I had my lower oil cooler hose and the water pump on my '93 replaced a couple of weeks ago. The ground underneath my car stays completely dry! :D

As for engine damage after the switch to syn, I have a hard time believing this is going to be an issue. If your engine is *that* dirty, you'll have other issues you need deal with.

However, one advantage that syn oils (I mean the real synthetic stuff, not the hydrocracked stuff) have over dino oils is the the pour point. It will stay much more fluid at very cold temperatures where dino (and hydrocracked "syn" oils) turn solid. Here in Cheyenne and Laramie where the winter temps can dip to -30*F, I can fire her up without much hassle. If I had dino oil in there, I wouldn't attempt it. However, when it's that cold out, you'll normally find me in front of my fireplace and not at work. :bouncy:

So, to answer one of your questions directly, I'd say "yes" the EOLI is worth looking at as it will help you schedule your oil changes. When it gets down to 30 or 20 or so, you can schedule the oil change. That translates to about 5,500 or 6,000 miles. Having the "Change Oil Soon" telltale is nice in case you forget and so you won't have to look at the EOLI all the time. Any sooner would be a waste of syn oil. If you were running with dino oil, you'd change it when the EOLI hit 50 and you wouldn't want to wait until the telltale came on. That's about 3,500 miles. I find that's consistent no matter how I drive or how cold it gets. That lends credence to the theory that the EOLI pays attention to just the crankshaft revs and the odometer and not the vehicle speed and coolant temps.

As for Jiffy Lube....man...I say stay as far away from them as possible. They've left the oil filler plug out of my 4x4 xfer case. I drove 50 miles in 4x4 mode. When I got home they called me. I had it towed to the Nissan dealer. They had to rebuild it on the spot - it was full of rocks and sand. Jiffy Lube paid for it but I had to argue with the store manager. Then they left the wingnuts off the airfilter cover. After that, I never went back. My brother went there and they didn't check if the old oil filter gasket was off the oil filter mount before installing the new oil filter. He left trailing oil out of the service bay. If I have to inspect their work every time they change my oil, what's the point? They seem to get a new crew (high turnover) every few months. Plus, I understand they use Fram oil filters - I avoid those at all times - they're made of cardboard and adhesives that reportedly fail frequently.

Cheers,
Tim

Night Wolf
08-03-03, 04:22 PM
I change my own oil.....

....I switched to Mobil 1 syn. Although my car isn't on the road yet, and I am not driving, I do run the engine often, not just at an idel either, I race it some times...should be on the road in the next few days, anyway, with 80k miles, there are no leaks to be seen, oil level is the same as when I put it in, so far it's good, if there are no leaks and such, then I will stick with syn. I am sure I'll also be a little hard on the engine from time to time, so the syn would help there too.