Mechanical problem, Any suggestions??

[mporto]

I have a '99 gmc yukon showing no compression in the #7 cylinder. If anyone has any experience with this problem please give me some suggestions on how to proceed.

Thanks

 

[SunlitComet]

Only 4 thing I can think of:

1. Gauge was not seated properly
2. Your piston has a hole in it
3. Your valve is stuck or bent open
4. Rings are really gone

Pulling your cylinder head for inspection my be your only choice. Do you have access to a boroscope to stick done your plug hole?

 

[longstand]

Just a cheap suggestion.

Drop 1 Can of Sea-Foam inside.

the probe the cylinder hole for any piston hole.