“I recently obtained a ’98 V70 w/102K miles that has an undiagnosed exhaust smoke problem. I decidered to resolve the issues I knew about first and eventually find the source of the smoke. Having already performed a PCV system replacement on my ’96 850, I confidently jumped into the job on the 70. I noticed that the turbocharger had quite a bit of oil showing on the outside, and also showing on the inside of the pipes leading to the intake manifold. My initial thoughts are that this is my smoke source, and wondering if it’s a result of the plugged PCV or if a new turbo is needed? I guess I won’t know until I’ve driven it for a while and then check to see if the turbo is still hemoraging oil. While in the middle of the job I figured I would replace the spark plugs being as it is new to me and I don’t know how old they are. To my dismay the plugs on cylinders 4 and 5 were oil soaked and I could see the top of the piston on #4 was black and rough textured. Bad rings? (Couldn’t see #5, too low) So now I’m thinking that my next step is to do a compression test on the cylinders. Now I finaly get to this question, is this something I can do myself? What is the procedure and what tools will I need? Any thoughts on the turbo?
“Running a compression test is easy. You need a screw in Compression tester, you can get cheaper press on ones but they are almost useless. Remove all 5 plugs screw in the compression tester then spin the engine over on full throttle after removing the fuel pump fuse and lead from Coi, after half a dozen spins you should have a good compression reading make sure its within the specifications or within at least 10%, for an 850 the compression should be 13-15 Bar for N/A & 11-13 Bar for T5.”
— MVS member CharlyW.