Just recently I bought an old '95 Seville STS with around 130K miles on it.
After every approx. 1000 miles, the "check oil level" message shows up and I need to add 1 liter (1.1 quarts) of oil.

I am quite sure that I am not losing oil as I never found any oil laugh below the car. Only thing is, that on the left side exhaust end I can see residues of soot on the rear bumper. However, I am not sure if this is caused by the oil problem. The soot isn't oily and therefore at least I am sure that the oil is "properly" burned.

The car drives very well and I believe that it still delivers maximum performance.

Does anyone have an idea of
- what could be wrong with the engine?
- parts that should be replaced anyway because of the high milage?
- and how much labor could be involved?

Any ideas are very welcome.

thanks

I believe your car comes with the NorthStar engine, so I would repost it in that section, for better reply results..

Personally, 1 qtr every 1000 miles isnt a terrible loss if the engine is burning it, especially if your car has higher miles like you do... My 95 deville has 72k and I add a qtr of oil every 1500k or so.. From what ive read in here, the northstar engines have an 'aggressive' cross-hatch patern on the cylindr walls, this helps to keep a film of oil to protect the piston rings better, but as a side effect, we burn more oil... The price of a qtr of oil ($1.25-$3.50) every 1000 miles is a small price to pay.

Thanks Concours95.

I'm driving US cars since more than 10 years. That included cars with 5L smallblocks and supercharged 3.8L 6 Cylinders (Ford & GM). None of these cars burned more oil than 1 qtr per 30K miles.
Therefore I was so surprised to see such a high oil consumption on the Northstar engine.
However, in the meantime I found many other postings related to this topic, claiming to have a relatively high oil consumption.

Obviousely this seems to be normal to the Northstar engine. I just wonder why BMW, Mercedes and Audi V8 engines consume much less oil.

If it is normal that the Northstar burns 1 qtr, then I am fine with that. I don't have a problem to pay for the oil, but I wouldn't like to invest thousands of dollars into an engine revision.

You've been lucky then probably if none of your engines burned more than 1qt per 30k. How can you tell how much it's burning though if you do multiple oil changes between 0 and 30k?