Mazda friends I am planning to do a compression test on one of my P5 tonight and I am looking for compression specs for me to look for. If anyone knows what the compression should be please let me know. I look forward to your responses.
I do not have the FSM. Also, I am new to this compression test thing so all of the information I can get will be helpful. Thanks for your response The_big_dill.
Thanks ap123! I did the test dry and I got 185 all around is that good? I see that on your thread you had 165 dry. Please tell me if it is necessary to do the test wet as well. Look forward to your response.
Thanks ap123! I did the test dry and I got 185 all around is that good? I see that on your thread you had 165 dry. Please tell me if it is necessary to do the test wet as well. Look forward to your response.
well technically its not absolutely necessary but it is good practice to do so.
Reasons you want to do the test both ways:
Gauges are not all ways accurate
Older engines have carbon build up on the piston, this will cause false high compression results.
Engine temperature at time of test, if the engine is not at operating temperature this will yield low results.
Testing it dry and wet will ensure your results are accurate. If you already have all the spark plugs out and everything no reason not to do it.
Mazda specs allow for a lot of difference but rule of thumb cylinders that test within 10 psi of each other indicate heathy cylinders. Wet and dry test results within 10psi of each other indicate healthy cylinders.
The results you got so far sounds like you have a healthy engine.
