GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi Im David, thanks for using the site. did you say that when you added oil to the cylinders that you got compression to come back up?
Sorry to tell you that thats not good. That means the piston rings are shot.
anytime a vehicle fails a compression test. we pour oil into the failed cylinders. if the compression comes up, that means the rings are bad. it it doesnt come up it means the valves are bad.
you have oil getting past the piston rings. they are supposed to pull the oil that is used to lubricate the cylinder walls back down. a replacement is probably cheaper than a rebuild.
you are welcome. sorry to bare the news. please leave a 5 star rating and accept the answer if you were satisfied with my help. thank you. have a good one.
did you decide on a rebuild or replacement?
checking in to see how its going