I have searched a few forums and found several people with oil consumption issues. I have just purchased a 2000 STS with the 4.3 this last August. the engine uses about a quart every 400 miles or less. It does not leak oil nor blow smoke out the pipe. Some posts have recomended
driving the engine hard to loosen the carbon build up on the piston rings to free them up. This hardley seems probable. Has anyone used any additives in the oil to reduce carbon or to help reseal the bores? Any other takes on this. I find the oil consumption extremely high for 1000,000 miles. Other Chevrolet vehicles that I own ( have owned ) would only use 1/4 quart after 2500 miles with 150,000 miles on the engines. This problem with the Cadillac is disturbing for such a nice vehicle. Any suggestions?????
Thanks, ken

ORIGINAL: vette355

Some posts have recomended driving the engine hard to loosen the carbon build up on the piston rings to free them up. This hardley seems probable. Any suggestions?????
Thanks, ken


Cadillac engineers recommed WOT because it does tend to work.

If you don't like that then use GM Top Engine Cleaner in the liquid form. Instructions are on the can. You would be advised to wear protective clothing andeye protection too.The engine may stall and chuck outcleaner. If you let the cleaner soak in overnight your results may be better. Once the engine starts to run theexhaust will smoke heavily. It might get embarassing, not sure what type of neighbours you have so be prepared for that. You may also get some codes showing up as engine stalls and stumbles so they will need to be cleared after you are done.

Thank for the quick reply. Idid redline the engine 3 to 4 times in second and third gear a few weeks ago with no change. Will try the same a few more times. Have a good one.
Ken

Remember you have nearly 8 quarts of oil in that crankcase. Mine usually need a quart when it hits 35% to 30% oil life left, so I suppose that is a quart every 2,000 miles or so.

Any sign of cold start knock, that would be a sure sign of some carbon build up. These are zero tolerance enigines.