I changed the oil in my car (1997 Volvo S90 with approx 200k miles on it) about 2k miles ago, and recently took a couple long car trips (~400 miles each, up and down mountain roads, etc). When I returned from the last trip I had to do some work and thought I would change the oil as long as I was under the car. The car is supposed to have 5.8 quarts, but I only had 4 quarts in my jug. I was concerned so did a compression test with the following results:
Cylinder# | Dry pressure (PSI) | Wet pressure (PSI)
1 | 205 | 235
2 | 190 | 215
3 | 100 | 165
4 | 152 | 215
5 | 175 | 215
6 | 205 | 235
I am a bit concerned about cylinders #3, 4, and 5. Is there something I can do to narrow down if the low compression is due to a head gasket, or ring damage?
As stated, the car is a 1997 Volvo S90.