No compression question

[bizer]

Hello. I recently sold my 1997 Explorer w/ SOHC 4.0 to my brother. The truck has 110,000 miles on it. Anyway, he was driving back to Arizona (from Minnesota) and the tensioner pulley blew (pulled it right over and shutoff). He had it towed and fixed. He continued to Arizona and arrived at his place. He had to bring it in to get the speedometer fixed and while there they checked it over. They told him the #3 cylindar had no compression and that the motor was shot. The motor does not leak any fluid or smoke when running. He says it runs good except for a loss of power. I had always done the service work on it when I had and it was a good truck. Anyone have a similar experience? He is driving it back here (Minnesota) to get it looked at. Any ideas what to check for?

 

[BigDakota]

I am just a shade tree mechanic, Well I have a garage too..but if there is no compression the odds are a compression ring in #3 is stuck or totally shot or one of the valves in the head for that cylinder is not working correctly.I am not sure if a bad headgasket would cause this, if it was, I think you would get coolent leakage.. The valve could be,warped,burned or carboned up so bad that it does not seat correctly to seal in your compression.It would be nice to have one of those flexable camera probes that can be stuck into the sparkplug hole to see the valves and cylinder walls.
Good Luck!

 

[Billy177]

besically the only way to get 0 compression is an open vlave, chances are that it bent when tensioner broke the piston smacked it