: northstar oil consumtion



fullserviceman
07-10-05, 11:06 PM
I now know via this forum that northstars use oil from the start. My question is does the cadillac dealer tell you this when you buy 1? How do you know? I just cant picture alot of the people who buy caddy's today checking or adding oil. My deville has gone at most 2 quarts low on oil without me knowing. This makes me hesitant to buy a used cadillac if maybe the first people to own it ran it with low oil more than a few times.. Whats the deal

MWA
07-10-05, 11:19 PM
My 98 Eldo used almost a quart/1000k when I purchased it used from a very reputable dealer and was told that this was not unacceptable. The service tech who changed the coolant and trans fluid and checked the alignment, belts, hoses, etc related to me the same thing that others say about the N*...run it like you just stole it. An older gent in his 80's owned it and never ran it. After each WOT the oil consumption subsided, yes it gradually is down to no noticable
consumption between changes now. It had 40k and now has 80k with no mechanical problems. Check other sources on this forum...run searches and read the threads and others including technical engineers here suggest the same thing. Run the hell out of it...after all the proper fluids and maintenance checks have been made. The older gentleman had seldom run it over 55mph. (the service tech at the dealership told me this behind the scenes) Enjoy the power of that N*!

BeelzeBob
07-10-05, 11:49 PM
All Northstar engines had/have the low oil level warning system to warn the owner if the oil level is low so there is little concern over a previous owner operating the engine too low on oil. Besides, with 7 quarts in the sump the engine can go a long long way before it gets low enough to really hurt anything.

Based on the total absence of any lower end or bearing problems reported on this forum (or others I frequent) with the Northstar engine I think it's track record in that respect is pretty good and is not something that I would worry about in the least.

Ranger
07-11-05, 12:16 AM
I check mine regularly and don't add til it just drops off the dipstick. that's about 2 qts. Like Bbob said, you still have 5 - 5 1/2 in the sump. No worries mate.

fullserviceman
07-11-05, 05:15 AM
Very good points,and I never thought of the 7 quart oil pan thing. I love my northstar and will buy another. I just know how people who own $50,000 vehicles usually don't know what maintenance is thats all..

dhstron
07-11-05, 10:17 PM
I have the same concerns about oil consumption. I have asked my dealer about it and they have advised me to bring the car in for an oil change and they will monitor the oil concumption every week to determin if the oil consumption is out of range. I am not sure what they will do if they find out I am using one quart every 400 miles.

Ranger
07-11-05, 10:28 PM
A qt. per 400 miles is excessive. They will likely change the pistons and rings after they try a carbon cleaning proccess. Have you tried the WOT treatments? Go to Technical Archives in the upper left corner of this page and read up on oil consumption.

Firewireman
07-11-05, 11:37 PM
First, what does WOT stand for?
Second, check your oil pan gaskets! Mine is starting to go bad and use an extra 2 quarts between changes. Not a huge deal, but enough to be annoying. It's never fun when an engine warning message comes up, no matter what it is.

WoodShoe
07-12-05, 10:28 AM
First, what does WOT stand for?
Wide Open Throttle. I like to call it the 'stand on it' method. Which my car sees more of than regular driving, and it still uses oil like the day I bought it. I don't understand how oil consumption can decrease that much for people on here, simply from driving it hard? I usually reset my trip meter and add 1L per 500Km ... seems to keep it happy. Although I have run it untill the check oil level light a few times...thats what its there for right ;)

Ranger
07-12-05, 02:03 PM
I don't understand how oil consumption can decrease that much for people on here, simply from driving it hard?
It has to do with carbon build up on the upper compression ring preventing the ring from moving in the ring grove and sealing properly. Bbobynski explaines this much more elequently than I if you can find the post.

WoodShoe
07-12-05, 06:07 PM
What I mean is, some peoples posts claim that their N* uses almost no oil between oil changes. After they started driving it hard...


After each WOT the oil consumption subsided, yes it gradually is down to no noticable consumption between changes now

No noticable consuption between oil changes? If i didnt add any oil 2 our caddys between oil changes they would dehydrate....

LT5
07-12-05, 09:26 PM
If i didnt add any oil 2 our caddys between oil changes they would dehydrate....


:yeah:

Ranger
07-12-05, 10:00 PM
Each engine is different. Some have a more aggressive hone pattern than others. Some burn more oil than others. Read the "Oil Consumption" in the Technical Archives at the top of the page. I think that may explain it.

blb
07-13-05, 08:16 PM
You'd think GM engineering would work on more closely on controlling the surface texture (ie: hone depth) of the cylinder walls and the other factors that lead to excessive oil consumption so there wasn't as great a disparity in oil consumption from engine to engine. After all, the Northstar has been in production since 1993!

Instead, the word from GM Engineering seems to be not to worry about it since the system holds 7 quarts and there's a light to warn you when its time to add more oil.

This would not be considered acceptable, and it is not the answer you would see in print, from the major foreign auto manufacturers that are known for their quality.

dkozloski
07-13-05, 09:08 PM
My '04 CTS with a 3.6L VVT V6 Northstar uses absolutely no oil. Cadillac has the problem well in hand. Oil consumption in North*'s is a thing of the past.

BeelzeBob
07-14-05, 12:18 AM
You'd think GM engineering would work on more closely on controlling the surface texture (ie: hone depth) of the cylinder walls and the other factors that lead to excessive oil consumption so there wasn't as great a disparity in oil consumption from engine to engine. After all, the Northstar has been in production since 1993!

Instead, the word from GM Engineering seems to be not to worry about it since the system holds 7 quarts and there's a light to warn you when its time to add more oil.

This would not be considered acceptable, and it is not the answer you would see in print, from the major foreign auto manufacturers that are known for their quality.


You guys keep beating a dead horse about oil consumption on older model engines. The oil consumption with Northstars has not been an issue for many years now on current model engines. The older engines out there will still continue to use varying amounts of oil depending on the cylinder wall finish and carbon buildup in the ring lands, etc... Somehow the changes incorporated into the 2000 and later engines did not magically fix all the earlier engines out on the road...LOL.


Quite honestly, I think most people make WAY too much of a big deal about oil consumption. The engine was engineered to use some oil by design. Engineers that develop engines do not consider this a bad thing when you have an engine making over 1 HP per cubic inch and revving to 6500 RPM regularily. Customers saw it differently and changes were made....but....if it were my engine I would not worry about it using a little bit of oil at all. In fact, I would like it to use some as that keeps the upper rings and cylinder walls lubricated better. That is one reason that people tear the Northstars down with over 200K on them to find the cylinder walls perfect with no wear and no wear ridge at the top.

You must not have read many of the oprevious posts on this subject if you think that Cadillac Northstars are the only engines that occasionally use some oil. Your comment about the foreign manufacturers not having this problem and not putting things like this in print is pure BS and shows your ignorance on the subject.

BMW specifically says in its owners manuals for the M series cars (their factory hot rods) to check the oil at every fuel stop during high speed driving as the engines can use enough oil so as to be low enough to cause engine damage during the next tankfull of fuel. There were quite a few M series engines replaced by BMW due to high oil consumption and owners actually running the sump dry enough to starve the engines. BMW considers some oil consumption like this to be perfectly normal, also.

If you check Lexus, Toyota, Mercedes, Honda, etc....they ALL have statements in print in their service literature to the effect that some engines may use oil at "abnormal" rates and yet be perfectly fine. The degree to what the different makes use to define "abnormal" varies but is in the 800 to 1000 to 1500 miles per quart range. In the case of BMW, a couple of quarts in a tank of fuel at high speed is still considered "normal" or "acceptable". Any engine like this is considered perfectly fine and simply at the high end of oil consumption. No different that what Cadillac says about the Northstar.

Firewireman
07-14-05, 12:29 AM
I did my first WOT today. I had something unexpected when I redlined, my tires chirped! I knew I had some power under my hood but holy crap! Car seems to be doing fine, nothing exploded, I'm still alive lol. :thumbsup:

dkozloski
07-14-05, 01:46 AM
Pratt & Whitney says that your R-985 aircraft engine is using too much oil when you can't carry enough oil in the oil tank to get you where you want to go. Design usage is about .015lbs/BHP/Hr. North* owners need to count their blessings.

fullserviceman
07-14-05, 04:17 AM
I will keep that in mind when I am at 39,000 feet and the oil light comes on and the dealer never mentioned anything about using oil.

blb
07-14-05, 08:20 PM
The oil consumption with Northstars has not been an issue for many years now on current model engines. The older engines out there will still continue to use varying amounts of oil depending on the cylinder wall finish and carbon buildup in the ring lands, etc... Somehow the changes incorporated into the 2000 and later engines did not magically fix all the earlier engines out on the road...LOL.

You must not have read many of the oprevious posts on this subject if you think that Cadillac Northstars are the only engines that occasionally use some oil. Your comment about the foreign manufacturers not having this problem and not putting things like this in print is pure BS and shows your ignorance on the subject.

BMW specifically says in its owners manuals for the M series cars (their factory hot rods) to check the oil at every fuel stop during high speed driving as the engines can use enough oil so as to be low enough to cause engine damage during the next tankfull of fuel. There were quite a few M series engines replaced by BMW due to high oil consumption and owners actually running the sump dry enough to starve the engines. BMW considers some oil consumption like this to be perfectly normal, also.

If you check Lexus, Toyota, Mercedes, Honda, etc....they ALL have statements in print in their service literature to the effect that some engines may use oil at "abnormal" rates and yet be perfectly fine. The degree to what the different makes use to define "abnormal" varies but is in the 800 to 1000 to 1500 miles per quart range. In the case of BMW, a couple of quarts in a tank of fuel at high speed is still considered "normal" or "acceptable". Any engine like this is considered perfectly fine and simply at the high end of oil consumption. No different that what Cadillac says about the Northstar.


The issues with oil consumption in the BMW M series engines and some of the others too, is nothing new and has been well documented. The difference is, the M series engines were marketed to those individuals who wanted a high performance vehicle and were more likely to be a "gear-head" type who would be more likely to understand the trade off of higher oil consumption due to the design of the engine. In contrast, the Northstar powered vehicles, in the mid 90's were still marketed to the older crowd, who just wanted a comfortable full size vehicle and many never have even considerd flooring the accelerator and they certainly didn't want to have to add oil between changes. But the biggest issue, was the great disparity in oil consumption from engine to engine, which to many people, spelled out the perception of inconsistent quality control with the manufactue of the engines.

As a matter of fact, BMW and Mercedes are no longer on many peoples "quality foreign car list" due to their terrible reputation for quality that has emerged over the last several years. In my previous post, I was thinking more specifically along the lines of the different families of the Toyota and Honda engines, none of which have the oil burning reputation of the Northstar engine. If anyone can think of any Honda or Toyota engine families noted for oil consumption, speak up.

Of course, ocassionally any manufacturer is going to have a problem child in the bunch and again, the GM dealers (at least the ones around here) don't want to even talk to you about oil consumption unless you're using a quart or more in 600 miles. By contrast, if you own a Lexus and you're going more than twice that distance on a quart, they will try to help you out. I have never seen in print in any Toyota or Honda publication that a quart in 600 miles is considered acceptable. If anyone can produce such a document, please elaborate. I guess it's all comes down to a matter of philosophy and to what standards you are working too.

If anyone knows specifically what changes were made to the Northstar to reduce oil consumption and what model year was the first to benefit from those changes, and is willing to share that information, that might be good information for those considering the purchase of a used Caddy. Also, if the miles per quart of oil consumption deemed acceptable by GM on the Northstar has changed after the engine was improved, that figure would be of interest also.

dkozloski
07-14-05, 11:38 PM
fullserviceman, the difference is that it is the pilots responsibility to consult the operators handbook and be fully aware of the characteristics of the engine. This information is easily gleaned from the literature and accepted as part of the package. This is why pilots make the big bucks.

BeelzeBob
07-15-05, 02:01 AM
The issues with oil consumption in the BMW M series engines and some of the others too, is nothing new and has been well documented. The difference is, the M series engines were marketed to those individuals who wanted a high performance vehicle and were more likely to be a "gear-head" type who would be more likely to understand the trade off of higher oil consumption due to the design of the engine. In contrast, the Northstar powered vehicles, in the mid 90's were still marketed to the older crowd, who just wanted a comfortable full size vehicle and many never have even considerd flooring the accelerator and they certainly didn't want to have to add oil between changes. But the biggest issue, was the great disparity in oil consumption from engine to engine, which to many people, spelled out the perception of inconsistent quality control with the manufactue of the engines.

As a matter of fact, BMW and Mercedes are no longer on many peoples "quality foreign car list" due to their terrible reputation for quality that has emerged over the last several years. In my previous post, I was thinking more specifically along the lines of the different families of the Toyota and Honda engines, none of which have the oil burning reputation of the Northstar engine. If anyone can think of any Honda or Toyota engine families noted for oil consumption, speak up.

Of course, ocassionally any manufacturer is going to have a problem child in the bunch and again, the GM dealers (at least the ones around here) don't want to even talk to you about oil consumption unless you're using a quart or more in 600 miles. By contrast, if you own a Lexus and you're going more than twice that distance on a quart, they will try to help you out. I have never seen in print in any Toyota or Honda publication that a quart in 600 miles is considered acceptable. If anyone can produce such a document, please elaborate. I guess it's all comes down to a matter of philosophy and to what standards you are working too.

If anyone knows specifically what changes were made to the Northstar to reduce oil consumption and what model year was the first to benefit from those changes, and is willing to share that information, that might be good information for those considering the purchase of a used Caddy. Also, if the miles per quart of oil consumption deemed acceptable by GM on the Northstar has changed after the engine was improved, that figure would be of interest also.


One of the driving forces behind the Northstar engine design was the repeated "requests" from the field for MORE POWER. So the Northstar delivers. We never realized how seldom people would use the power or what a chore it would be to get them to put their foot firmly on the accelerator occasionally to at least keep the carbon cleaned out of the engine.

Lexus oil consumption guidelines that I have seen consider 1000 miles per quart or slightly less perfectly acceptable. If you look thru the service literature of any of the autocompanies you will find similar guidelines.

Mercedes and BMW have dropped down on people's quality ratings primarily due to electronic and electrical problems....not due to oil consumption. The JD Power data is very clear on that. In the rush to incorporate all the latest electronic content there were some bugs, apparently.

The current model Northstar engines have incorporated a variety of changes mentioned previously in this forum to reduce oil consumption. The cylinder wall honing process now incorporates diamond honing stones that provide a more consistent cylinder wall finish due to the extreme life of the honing stones. Piston design has been modified with revised oil drainback areas in the ring belt area, higher tension oil and compression rings and a revised ring face design. In addition the hard anodizing of the top ring land has been modified to make breakin of the top ring to the side of the ring land easier. The piston compression height has been modified slightly to increase clearance to the squish areas in the cylinder head making the chamber much less sensitive to carbon buildup and the "cold carbon rap" phenomenon.

In addition, there is a service piston design available for any post 2000 chronic "high oil consumption" or chronic "cold carbon rap" engines that can be retrofitted into the engine if desired.


Oil consumption on the Lexus (Toyota) V8's has been variable to some extent over the years as often reported in the Lexus forums.

You are overlooking the Toyota minivan engines that sludged themselves to death right and left due to an inadequate PCM system...??? I realize they didn't consume oil but if they had consumed a little oil then maybe there would have been some PCV flow and the engines wouldn't have sludged up so badly that they blocked the oil pickup and took out the bearings. This was a chronic problem several years back. Not throwing stones at Toyota necessarily but just pointing out that different problems crop up on different engines.

A little oil consumption does not hurt anything and is basically just an inconvenience of having to add oil occasionally. Once you understand how/why the engine uses oil it shouldn't be viewed as a quality issue to the knowlegable owner.


The changes to the engine are fairly effective as the newer Northstars that I have driven over the last few years have gotten around 5000 miles per quart of oil or better....

blb
07-15-05, 12:43 PM
bbob....excellent information. Thank you.

Yes, many people have learned that Toyota isn't flawless with the minivan engine sludge issues.......especially the people that used them for many short trips without changing the oil religiously.

So the majority of the revisions to the Norhtstar to reduce oil consumption were effective in model year 2000?

Also, since it sounds as though the oil consumption issue was essentially a balancing act between the quest for power while minimizing oil consumption, has a reduction in power been realized on the revised engines, mainly from the higher tension oil and compression rings and the revised ring face design?

BeelzeBob
07-18-05, 12:30 AM
The drier the engine is the more upper cylinder wear is going to occur over time and the faster the rings will wear. No way around it. If you dry up the oil on the cylinder walls the top end wear is going to increase.

That is why the Northstars that do come apart with 100K or 150K or more are always pristine inside and have no cylinder wall wear and still show the factory honing marks in the bore.

The drier engines are not necessarily going to wear out prematurely or anything but I would expect to start to see upper cylinder wear and such at 150K if one comes apart.

The higher tension oil rails and higher tension compression rings add more drag/friction which doesn't hurt power as much as fuel economy. The extra friction is a small percentage of the overall friction at full throttle but at part throttle running down the road the higher tension rings definitely add friction. Not a huge fuel economy loss but it is directionally incorrect and adds up over the long haul.

Some of the changes were in place in the 2000 model year and others were put into place in the following model years. I think that most all of the tweaks were in place for the 2004 model year if I am not mistaken.

JohnnyO
07-22-05, 05:03 PM
Some of the changes were in place in the 2000 model year and others were put into place in the following model years. I think that most all of the tweaks were in place for the 2004 model year if I am not mistaken.

I've said before, my mother's '99 might as well be a two-stroke and my dad's '04 doesn't burn a drop.
:elvis1:

El Dobro
07-22-05, 05:17 PM
When I had a '93 Allante with a N*, I didn't have to add a drop of oil between changes. Could just be luck of the draw.