2005 rendezvous p0305 code

[ramboldo4]

2005 rendezvous with 0 compression on cylinder #5 and service engine light with P0305 code description. wonder if problem internal mechanical engine problem (cylinder, camshaft) or collapsed opened head valve. Engine runs on idle with much hesitation and decreased power on drive. no knocking or other noises. Any help thanks..😕

 

[lrj975]

zero compression with no other symptoms like loss of coolant, smoke out the tailpipe etc is most likely either the intake or exhaust valve stuck open maybe due to carbon deposits around the valve and head resulting in poor valve seal, or the valve cracked. doubt it's an internal issue like cam or cylinder, need to remove head and inspect.

 

[ramboldo4]

you were right ; collapsed valve on 5 was causing the problem; replaced valve and running like new. of course went ahead and replaced cylinder head gaskets and all gaskets above that.
many thanks