Using motor oil


I have a 2006 Pontiac Grand Prix GP with the 3.8 litre V-6 that is using oil. I checked for leaks @ couldnt find any could someone tell me what could be causing this? I also made sure the car wasnt smoking from the exhaust that would indicate the motor was burning oil @ it isnt smoking.


How much oil? One quart between oil changes is normal or tolerable. And if you are burning oil excessively, don’t expect to see smoky exhaust. The catalytic converter on a modern car eats up the smoke.


If you’re sure there are no leaks, then the engine must be burning the oil. There are no other options. How many miles does it take for the engine to consume a quart of oil? This car is awfully new to be burning oil, but some engines consume small amounts of oil as part of their normal operation.

You don’t see smoke because the catalytic converter burns the small amount of oil in the exhaust. Your engine would have to be burning a LOT of oil before you’d see the smoke.


It burns 2 quarts between oil changes. Thanks for the help.


The car only has 40,000 miles on it.


Adding a quart every 1,000 is considered acceptable by most manufacturers.


How often did you change the oil & filter? Did the car ever overheat really bad once or twice? I’d put a piece of cardboard under the engine overnight and look for a leak . . . if none, I’d fill it to the “full” line, drive 500 miles, then check again . . . to see what your oil loss actually is. As Rod Knox said, 1 quart every 1000 miles is considered OK by some car makers . . . not necessarily me, but within limits by some. Rocketman


Have you discussed this with the dealer? I think there may be a warranty issue here. I suggest you read the warranty information that came with the owner’s manual, then go visit the dealer service department. This vehicle should not be burning this much oil. I hope you can demonstrate to the dealer that all required oil changes have been performed on time.


One cheap thing to try would be to change the PCV valve. They’re cheap and can sometimes cause unusual oil consumption issues if they plug up.

Are you just changing the oil when the “maintenance required” light comes on? If you’re driving mostly highway miles, the little computer thing that decides when to turn the light on will let you go a lot of miles before you need the oil changed, in which case 2 quarts might be well within a reasonable oil consumption rate. You just need to check your oil every time you fill up and keep some oil in the trunk to keep it topped off.