burning oil

~i've got a problem with an 2002 Cadillac ?SLS? Northstar. the car has about 40,000 miles. every thousand miles or so it burns about a quart of oil. the lower the oil level the worse it burns. was taken to the dealership and they said this was normal. i digress, why would you build an engine that burns oil so rapidly on such a late model car? anyways, any information would be highly appreciated.


~thanks

A quart every thousand miles? No mechanic in their right mind would tell you that this is normal. They just don't want to pay for repairs (if its under warrenty). If you do have a warrenty, take that sucker back or to another dealership and have them fix your problems. It sounds like your seels are gone if its actually burning and not leaking.

A quart every thousand miles? No mechanic in their right mind would tell you that this is normal. They just don't want to pay for repairs (if its under warrenty). If you do have a warrenty, take that sucker back or to another dealership and have them fix your problems. It sounds like your seels are gone if its actually burning and not leaking.


~i know it sounds crazy!!! i'm going to call around to other dealerships and ask them if its natural. just so i can say that someone else at another dealership said it wasnt. i mean damn, thats a lot of oil.

I worked for Cadillac dealers for 27 years. I found most Northstars went 900 to 1000 miles per quart. The oil is going thru between the valve guides and the heads. There has been a problem with this since 1994. Instead of fixing it, GM issues a bulletin that states that 1 quart of oil in 700 miles is normal and no repairs should be attempted. I'm glad I retired. I was running out of excusses for GM's poor engineering. It started with the diesel, then 8-6-4, then HT4100. I'm supprised I don't drink more.

I've had two Caddys with that problem. The first one, an '85 Seville was taking a quart with every tank of gas at 50,000 miles. I switched to 20w50 oil and it stopped for the next 115,000 miles. At 165,000, it was getting a little blowby. I stopped in at a ten-minute oil change one day. They were training a new guy, and he forgot to put oil back in it after draining the sump and changing the filter. It ran for about 10-15 minutes with no oil in it!! Mostly at idle, as it would not revv up. I drove it around the block after it had sat getting cleaned while idling with the A/C running. After putting oil back into it, it ran normally, and the blowby was gone!! My '96 Consourse began to burn excessively at around 150,000 miles and I switched to 20w50, and the excessive oil consumption stopped. The owners manual warns specifically against using 20W50 oil. They want your car in the junk yard before it gets old and cheap.

I have seen an unpublished Cadillac SR that describes some kind of acid soak that disolves excess carbon residue on the ring grooves.

My 97 STS with 80K on the odometer burns....sorry uses a quart every 800 miles. Dealership says this is within spec and not to worry. Suggested a chemical de-fouling of the ring surfaces and then run lower octane fuel. I question this because it has consumed oil since new and being a cheap-ass have always run 87 octane fuel.

Actually my old 1968 manual states that 1 qt per 800 mi is not considered excessive. I would have to look at my other manuals to see what they say and I agree that the dealers will tell you anything to get out of doing warranty work.

You should still have the original facctory warranty. It's good for 4 years or 48,000 miles from initial delivery unless you got it as a "certified pre-owned Cadillac", in which case you have 6 yr, 100,000 mi.

As far as oil weight, I use 20-50 in my 1968, because it is in serious need of an overhaul and that oil helps me prolong the inevitable (the bloodletting of my wallet for a proper overhaul). My other Cadillacs all insist on either 10W-30 or 5W-30 :eek:

I suspect that this is because the EPA and CAFE dunderheads will go after them if they recommend anything else, because the heavier oils are little bit more viscous, meaning they "use more energy" than the lightweight 10W and 5W- oils. This of course would mean lower gas mileage, but who the hell cares if it lowers consumption.

As for running 87 Octane, I'm not sure that that's such a great idea in a 1997 STS or ETC, because the high strung NorthStar didn't like regular fuel back then. Cadillac reworked the NorthStar system in 1999 to run at full power on 87 octane. As long as you don't get any knocking, you SHOULD be ok, but don't be a leadfoot.

Jed is corect. GM says 800 miles a quart is within spec. At my old dealership we did a "De-Carb" on the engine which breaks up all the carbon inside the engine. Sometimes this would help to alow the consumption of oil. If your under warranty I recomend complaining of a cold knock condition, and they should perform a de-carb on the engine.

I got a '96 ETC that does mostly stop & go city. It uses a quart at around 2,000- 2,500 miles and it has 93,000 miles on it. 1 quart per 1,000 is wrong under normal driving. I made a 1,000 mile trip into Nevada at 85-95MPH most of the time and it used a quart then.

STAY THE HELL AWAY FROM DEALERS! I can't stress this strongly enough. Find an honest independent mechanic by asking people you know. Only time I took my car to dealer was for warranty stuff. And then they try to "find" other stuff you "need." If you go to a dealer after your warranty is up, bend over!
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The Northstars have loose oil ring tolerances because they are a performance engine. The problem arises when the owners drive the cars like little old ladies and the rings get gummed up with carbon. Usually a couple of full throttle blast from 0-60 in 2nd gear will clear the problem up. The Northstar is an engine that likes to rev, and needs to to keep the rings clean. The newer engines have a redesigned oil ring that helps this problem.
But the 1 quart in 1,000 miles is perfectly normal. My 2000 STS has 20,000 miles on it's engine and it uses about that.

The Northstars have loose oil ring tolerances because they are a performance engine. The problem arises when the owners drive the cars like little old ladies and the rings get gummed up with carbon. Usually a couple of full throttle blast from 0-60 in 2nd gear will clear the problem up. The Northstar is an engine that likes to rev, and needs to to keep the rings clean. The newer engines have a redesigned oil ring that helps this problem.
But the 1 quart in 1,000 miles is perfectly normal. My 2000 STS has 20,000 miles on it's engine and it uses about that.

Here here, the Northstar is pretty much a toned down racing engine, and I question GM's sanity for putting it in almost every Cadillac made since '93. Yes it's a hell of an engine and has proven itself over time (with fairly little fuss) but it wants to GO and REV, driving it around town and taking it easy is not what that engine wants to do. I actually know people that REFUSE to put the pedal to the floor!!! They say "it will hurt my car". RUBISH!!! As far a the seals from the factory being faulty? You would think that at some point between '93 and now they would have fixed that wouldn't you say? There are way too many Northstar owners with complaints about oil consumption (from '93 on) for it to be bad seals. Hi-po engines use oil, it's a fact not a problem.

Face it folks it's a hot rod, drive it like one, get after it once in awhile.

And even though your car seems to run on 87 octane "alright", Cadillacs tend to isolate the driver from the annoyances of "outside" noises so I don't think you would even hear your car pinging if it was, especially with the windows up, A/C cranking, and the radio on. Look at the TSB's about fuel problems and they all say the same thing, 93 octane minimum, for that matter one says to drain the tank and refill with premium fuel if the customer is not running 93 octane.

And even though your car seems to run on 87 octane "alright", Cadillacs tend to isolate the driver from the annoyances of "outside" noises so I don't think you would even hear your car pinging if it was, especially with the windows up, A/C cranking, and the radio on. Look at the TSB's about fuel problems and they all say the same thing, 93 octane minimum, for that matter one says to drain the tank and refill with premium fuel if the customer is not running 93 octane.


Since he has a 2002 SLS, it will run fine on 87 octane. All 2000-up Northstars are designed to run on 87. The compression was lowered in 2000 from 10.3:1 to 10:1, but with the addition of roller cam followers, this made up for the power loss difference!