Short story, my 2004 XC90 T6 165K miles is for sale here, and I agreed to a pre-sale inspection. The Volvo “specialist” near me did a compression and leakdown test as part of a “bumper to bumper” 2 hour paid inspection. They found cylinders 1-4 had 135PSI to 140PSI and 5 and 6 were 60PSI and 95PSI respectively. They thought that it could be a combination of valves and/or scoring on those 2 cylinders. They stopped there and didn’t troubleshoot further, as they found this during the full inspection of my XC90.
Last night I tried to recreate those results to try to determine if it was rings or a head gasket or valves. I pulled fuse 6 under hood to disable the ECM so I didnt have fuel squirting everywhere while testing and skewing the results. I had >180PSI on all cylinders, but #5, which was at >150PSI.
I was using a brand new compression tester (I left mine at a friend’s house when we were working on his R32 and had to grab a new one at Advance last night) and after a few tests, it showed those higher pressures consitantly, even with a low battery from listening to the radio while I took everything off the top of engine.
Due to my lack of planning, I didn’t put it up on ramps or park it where I could get it on my lift to get access to front of the engine to spin it for the leakdown testing. I’m thinking I might be wasting my time doing that at this point, because the engine runs great and is low maybe a quart of oil after 10k miles. No exhaust smoke, no cross contaminated fluids. I’ve only done leak down testing to see if I had a bad headgasket, rings or valves when something actually blew and it wasn’t running or running right.
Here’s a link of the compression testing:
drive.google.com
Am I doing something wrong, or did the shop maybe have some defective tools?
I talked to one of my friends this morning who has a transmission shop and has a couple of bonkers turbo charged drag cars thinks everything is fine and questioned the shop’s methodology. His opinion is to not try to fix anything that isn’t broken, and he thinks everything is fine after looking at the videos. I’m just looking for some more definitive info. I can’t in good conscience sell it until the issue (if one actually exists!) is found and corrected. I’m pretty sure the guy who was interested in buying it is still interested, but we are confused as to why my results differ so much from the shop.
I’d appreciate any input, thoughts and advice!