Look on the dipstick it just may say it. From what I can tell from other post it is 10w30w
Been using full synthetic since 2001 in my 1998. I have no oil seepage, no smoking, no leaks, my engine is dry as is the driveway. I loose none between oil changes, it does not burn it off either, I use full synthetic 10w30 mobile 1. If you have seepage or loose synthetic then it would seep/loose it with any oil type. What does happen with oils of all types that is a newer issue is that the auto makers are shifting to a lighter oil instead of 10w30, its gone 5w20 now its 0w20 or less. This lighter oil can burn off because of seep past ring seals, gets burned off unnoticed. Can seep past all seals & gasket easier, back to 2004 they still used and designed for 10w30, just until about 2013-14 they still were designed 5w20, afterwards 0w20, depending on auto-makers some a littler later or earlier, Let me clarify you can still use heavier weight oil in these newer engines, if you have oil seep or leaks or loose oil level between changes moving to a heavier weight is perfectly acceptable.
10w -30 works... @e c ..i had a 89 rivi that couldn't use synth.. i guess it got better in the 90's.
Looking for a Used Bonneville in your area?
CarGurus has 432 nationwide Bonneville listings starting at $1,500.
Search Pontiac Bonneville Questions
Pontiac Bonneville Experts
Related Models For Sale