: Northstar oil burning - what to do?



gday2uDTS
09-20-03, 01:55 PM
Hey all,

My first post here, thought i'd try and find someone who can give me some advice here!

I have a 2000 Deville DTS, very nice, but it burns too much oil. The "check oil" light comes on within 1 month of servicing the car, so I end up putting about 3 quarts of oil in the car between services.

Currently doing the oil consumption test - been back 3 times and they said "yeah its using some oil" so they did a "piston flush" and now told me I have to go back every 1000 miles again to do another oil consumption test.

Does this sound reasonable? I've had the car in the shop for at least 3 weeks for different problem including this, and had to take time off work for all of these appointments so I need advice off someone here to see if i should be doing something else. (like complaining here....) :-)

jonrodman
09-20-03, 11:41 PM
Hey all,

My first post here, thought i'd try and find someone who can give me some advice here!

I have a 2000 Deville DTS, very nice, but it burns too much oil. The "check oil" light comes on within 1 month of servicing the car, so I end up putting about 3 quarts of oil in the car between services.

Currently doing the oil consumption test - been back 3 times and they said "yeah its using some oil" so they did a "piston flush" and now told me I have to go back every 1000 miles again to do another oil consumption test.

Does this sound reasonable? I've had the car in the shop for at least 3 weeks for different problem including this, and had to take time off work for all of these appointments so I need advice off someone here to see if i should be doing something else. (like complaining here....) :-)
I would like to know where the oil is going. Do you see blue smoke in the exhaust? Is the oil dripping on the ground? Sometimes oil consumption is the result of leaking intake valve seals. If this is the case, it is easily repaired with new seals. Of course I have never taken a NS apart and don't know if it has valve seals. Not all engines do, but if it does have valve seals and if that is what is allowing the oil to get into the combusiton chamber then that is a relatively painless repair. If it smokes more at idle than while driving it is likely to be the intake valve seals.

Possibly a stuck PCV valve will cause excess oil to be scavaged from the crank case to the intake system and then burned. That would be a very easy repair.

If the engine is running very hot a lot of the time, then the oil could evaporate over time and travel through the PCV system, into the air intake, and eventually out the exhaust.

Just a couple ideas. I am not a mechanic - but used to pretend. I was considering the least expensive possibilities before you sign up for a new engine or rebuild.

One more idea. Are you checking the oil yourself? Can you confirm that it starts out with the correct oil level and looses oil as you drive? If someone was not adding enough oil during changes then you would be starting out low and going lower from there. They take 8 or 8.5 quarts to fill up after an oil change. Most cars take 5 quarts. If someone was adding only 5 during a change, and you lost one quart during driving, then that would leave you four quarts low.

These engines seem like really high quality high tech clean burning engines and don't appear to me to be oil burners.

Jon

tstclr
09-21-03, 06:38 PM
You are getting carbon buildup in the engine causing the oil rings to stick in their grooves. When this happens they burn oil. At the dealership I work at a number or Northstar Caddy's fail emission tests due to high HC's due to burning oil(you can fix this BTW buy switching to synthetic oil wink wink). The decarbs rarely help for some reason. There are updated piston rings and we just noticed on a Seville we are doing rings to and accidently busted a piston: there are updated pistons now that have the ring grooves lower down on the piston- not sure if this design is to eliminate oil burning, but we were sure surprised when it showed up looking this way! No official word from GM on these new pistons yet.
Todd

Katshot
09-21-03, 07:58 PM
Bottom line: Cadillac says 1000 miles per quart is "normal" oil consumption for the Northstar, and therefore they will take no action to fix it. If the rate is higher than that, they will do the "de-carb" and as was said, it generally is less than effective.

botboy
09-23-03, 01:24 PM
You are getting carbon buildup in the engine causing the oil rings to stick in their grooves. When this happens they burn oil. At the dealership I work at a number or Northstar Caddy's fail emission tests due to high HC's due to burning oil(you can fix this BTW buy switching to synthetic oil wink wink). The decarbs rarely help for some reason. There are updated piston rings and we just noticed on a Seville we are doing rings to and accidently busted a piston: there are updated pistons now that have the ring grooves lower down on the piston- not sure if this design is to eliminate oil burning, but we were sure surprised when it showed up looking this way! No official word from GM on these new pistons yet.
Todd

Hey could you email me botboy60@hotmail.com? I have a couple questions for you about rebuilding these engines since not a lot of people do it.

jam224
10-06-03, 01:35 PM
Hello,

I was having some coolant leakage problems in my 97 DeVille not too long ago and everyone gave me some great advice. The problem is now fixed - not much coolant loss anymore. But I still have a strong burning smell coming from the engine compartment. At first I thought it was the coolant, but my mechanic told me its probably oil. The car burns about 1 quart per 1000 miles, which is not out of range, according to Caddy. But the smell is pretty strong. I really can't keep the windows down and I have the recirc button on always. The strange thing is there is never any bluish/white smoke coming from the exhaust. In fact, the exhaust smells better than the engine compartment. I have tried an oil additive (can't remember brand) but it didn't seem to do much. Any thoughts?

Thanks,
Jim

7615
10-07-03, 05:04 PM
You are getting carbon buildup in the engine causing the oil rings to stick in their grooves. When this happens they burn oil. At the dealership I work at a number or Northstar Caddy's fail emission tests due to high HC's due to burning oil(you can fix this BTW buy switching to synthetic oil wink wink). The decarbs rarely help for some reason. There are updated piston rings and we just noticed on a Seville we are doing rings to and accidently busted a piston: there are updated pistons now that have the ring grooves lower down on the piston- not sure if this design is to eliminate oil burning, but we were sure surprised when it showed up looking this way! No official word from GM on these new pistons yet.
Todd

tHE NEW PISTONS WITH THE RINGS CLOSER TO TH EBOTTOM OF THE PISTON ARE FOUND IN ALL NORTHSTARS FROM 2000 AND UP. THIS WAS DONE TO IMPROVE THE OIL SITUATION BUT ALSO DROPPED THE COMPRESSION ENOUGH TO BURN REGULAR UNLEADED FUEL. I THINK THE ALLOY IN THESE CANS HAS CHANGED ALSO.
JOHN

AirJigga25
10-07-03, 05:15 PM
Hello,

I was having some coolant leakage problems in my 97 DeVille not too long ago and everyone gave me some great advice. The problem is now fixed - not much coolant loss anymore. But I still have a strong burning smell coming from the engine compartment. At first I thought it was the coolant, but my mechanic told me its probably oil. The car burns about 1 quart per 1000 miles, which is not out of range, according to Caddy. But the smell is pretty strong. I really can't keep the windows down and I have the recirc button on always. The strange thing is there is never any bluish/white smoke coming from the exhaust. In fact, the exhaust smells better than the engine compartment. I have tried an oil additive (can't remember brand) but it didn't seem to do much. Any thoughts?

Thanks,
Jim

The smell is the smell of the oil burning...my car burns about a quart per 1000 miles. You usually smell the oil when you are slowing down or coming to a stop. Even though some people might not think this makes sense...Northstars have always used that much oil. They are guzzlers of oil. It used to annoy me to put more oil in my car all the time, now I enjoy it. My car runs great though.

possible solution: check oil regularly and add oil when needed.

El Dobro
10-07-03, 11:17 PM
My 98 SLS was getting around 1000 to a quart of oil. Under the extended warranty, the infamous case joint leaks were fixed. Then it was found that the head gaskets were leaking antifreeze and one of the sparkplug holes was leaking oil. This was repaired under warranty too. Now, the car gets closer to 2000 miles to a quart. In contrast, my Northstar Allante gets 3500-4000 to a quart.