A bit of background information, I recently picked up a cosmetically very tidy 850R but with multiple oil problems, one of which it blows blue smoke out the exhaust at random times. There is a long list of items to do that I plan to attack, like virtually all engine seals, PCV etc however its all pointless if the piston rings are worn and the engine needs a rebuild or replacement. I'd like to know with some degree of certainty that my piston/block is okay so I can proceed with tackling everything else. My car has done 290,000km and I'd like to know if it's in good enough condition (provided I look after it) to make it to the 400,000km mark. The below text is mine, ripped from another Volvo forum where I didn't get a satisfactory answer.


So the other day I did a compression test on my car using Robert DIY's method. My results for the dry test (Cylinder 1-5, in PSI) were 158, 153, 152, 158 and 156. For wet they were 195, 182, 195, 180, 181. These readings are while the engine is hot. My question is, is my engine okay and likely to last a while? Or do I need to do more tests to find out? I need to know before i spend money on replacing cam seals, timing belt, rear main seals, pvc etc. (Leaks from all of these). My car has blue smoke coming out the exhaust at random times (I couldnt see any today while warming up the engine during a 15 minute drive, although that doesnt mean there wasnt any). Is this from worn rings or something else? My car has 290,000km and as previously mentioned, theres oil in the air pipe going from the radiator, over the engine and into the turbo but I dont know why or what this means.

Im trying to rule out very major issues with my engine so I can proceed with all the oil leaks and smells and burning my car has. I dont want to do all these smaller items only to find my engine is toast. I appreciate your guys help, if I need to do more tests or provide more info I'm more than willing to do so. This car will be my winter project down under provided I dont need a new engine/rebuild and im very keen to fix it up.

Thanks

 

The smoke could be a turbo leaking a bit of oil. I was in similiar situation. Redid turbo . Pcv. Complete valve job. Left the block and transmission alone. So anyway id say leave the block alone

 

your compression looks fine. 150-160 is in range for a turbo engine - where the NAs are in the 180 PSI range. You were correct in doing the test on a warm engine. As to thing that could cause some smoke, there's a few. PCV system, turbo seals and valve seals come to mind. You didnt mention what the oil consumption level is - how often do you need to top off the oil level? Are you seeing any coolant consumption? How do the plugs look? I'd agree that the block looks to be in good shape.