1998 V70XC Compression Test Results

bubbeck · Post by **bubbeck** » 29 Oct 2017, 13:33

Hey everybody,

I was going through doing a Stage 0 tuneup on my '98 V70XC with 221k miles, and while replacing the spark plugs figured I might as well do a compression test to make sure its worth putting more time/money into the car. The engine isn't having any problems to my knowledge just figured I'd check.

I forgot about warming the engine up first, but I did the test with the throttle open and got ~170psi for cylinders except cylinder #4 which was ~162-164. Seems like most cylinders then are pretty good (I found 168 psi as a spec somewhere, can't find it again though), but should I be worried about cylinder #4? Is it worth doing the test again with a warm engine or should I just let it ride?

Post by **kahl** » 29 Oct 2017, 15:16

I think those are great numbers. On the two 98s I have both are swimming around 155 to 160. Both have about 185 on the clock. For giggles I would be interested in compression with the engine hot.

Post by **j-dawg** » 29 Oct 2017, 15:27

You're probably fine.

What's important isn't so much the exact numbers you get - those will vary according to ambient temperature, engine temperature, etc - but that all five cylinders are close to each other. The red flags only fly if one or more cylinders are a significant percentage below the others. Maybe you've got some gunk building up on a valve seat or something, but the things that justify deferring maintenance will bring your compression down way lower than that.

Post by **Roger_850T** » 29 Oct 2017, 20:44

I agree those are all pretty good! You have a pretty small deviation, but not something that I would tend to worry about. (If one were down more like 120 then I would worry.) Write them down, and check again in another 10k miles if you want to track it.

Roger

Post by **rspi** » 30 Oct 2017, 08:50

For the turbo engines the numbers should be between 156 - 186. All numbers should be within 15% of each other. Fifteen percent of 170 is 144. As long as your numbers are within that you should be good. Turbo cars can run fine with lower compression. As mentioned, as long as your numbers are above 125, you should be ok to keep driving.