WARNING: This video contains annotations that may not be visible on the YouTube Droid app. Compression test: 30 to 60 minutes. This video will show you how I…
How to do a compression test on a car motor. Volvo 850, S70, V70 through 1998 – Auto Repair Series
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Robert, So after learning that this motor had bad rings, what did you do?
Did you tear down and overhaul? And if so what specific procedures were
necessary to remedy the issue? Or did you just drop in a new motor? Just
preparing myself for the possibility of this same diagnosis on my 98 V70.
Thanks!
I went and pulled a motor from a wrecked 850. Takes about 2-1/2 hours to
pull a motor from the junk yard. I did a manual crank compression test at
the junk yard and got 90-93 psi from each piston. The motor in the video
car had low compression and the knocking bottom end. To many issues for me.
If you get low compression in #2 and the head gasket is bad, it will not
tell you anything about piston because the head gasket is leaking. The most
common problem with these cars is a burnt/chipped valve. If you have no
symptoms of a bad head gasket (i.e. you did NOT over heat the motor) the
most likely thing is a bad valve.
What will it show if the gasket is bad on the test and the pistons are
good? I can’t tell if my car had bad gasket or piston (or both).. No smoke
is coming out of the exhaust but it is misfiring in cylinder #2.
Yes you can but the numbers will be off, very low.
can you do the test without warming the motor first?
You are welcome.
Ok thanks, I should not have asked Can I , I suppose I should have asked
will this work properly if the car is cold. Thanks for your videos ,they’re
very helpful..
good video!