1997 bonneville 3.8 non turbo. PO was about to sell it to junkyard when I picked it up off him. PO was driving fine until driving with low oil heard a loud pop, overfilled the oil and it started blowing tons of smoke later.
Suspecting blown rings I've gambled on UIM LIM gasket replacement. LIM looked good. UIM gasket was slobbering oil on outside of engine and wet oil tracks where noted on inside of intake valve ports. removed 1/2 liter of oil from under UIM sitting on the UIM gasket. EGR stovepipe full of oil dumping oil into UIM. I replaced the PCV and made sure its got gaskets and all good.
replaced LIM and UIM gaskets and removed the oil from the EGR and made sure its not stuck opened and clean. Removed enough oil to dip stick hash marks and started it. It smokes thick with blue tint. I ran it for maybe a minute seeing if it would clear up and shut it down. Started it again to see if it cleared up 12 hours later. Initially no smoke but after 30 seconds it began with a little smoke then started dumping the heavy smoke again.
My problem is similar to Did upper intake now burns oil. Help
except there was no resolution in that thread except maybe changing the oil
Can coolant thin the oil enough to let it slip passed the rings? Ive taken the UIM back off and noted maybe 3 ounces of oil again in the UIM from maybe 3 minutes running and again the EGR stovepipe is full of oil. I may be hearing a slight metal on metal note when running. I cannot do a compression test because warming it up requires smoke so thick its a hazard to traffic (mechanicing on street curb) at this point I`m diving down to rings to see if one snapped or cracked piston, scored cylinder wall or cracked piston lands. I cannot figure out why the EGR is full of oil though. The smoke is 100% of the exhaust, meaning as thick as it can get leading me to believe something is horribly wrong. I also noted a small amount of metal dust in the 1/2 quart of oil I removed from the oil pan.
My next step it to drain the old oil and compare viscosity to the proper oil weight. The old oil has 15k miles on it. I did not change it because I suspect cylinder damage and would have to immediately dump it to go after the rings. Not a fan of dumping brand new oil.