New to posting, but I absolutly love this forum!
I have a 1990 RS V6 3.1 and zero compression in my number 2 cylinder. (I overheated it bad last week and it blew off the bottow radiator hose at the engine) No other water leaks that I saw, I ran the car a few times around town to get a couple of tools and still nothing. Did a compression test and all were good except #2 was zilch! Ugh....

I have pulled the heads out thinking it would be a head gasket or a valve. No breaks or signs of leakage in the head gasket that I can see. Will pull the valves out next to check them out.
Question is... what else should I be looking for?

Thanks for the help!

 

well since you pulled the heads out, how about pouring some thin oil into that cylinder and see if it seeps through... if it does, then diagnose no more...

You weren't using synthetic, were you?

 

Based on your description of events leading up to the issue I would concentrate on the rings. Severe overheating can burn the rings to the point significant blow-by causing no compression.

Unfortunately you've already disassembled the motor. Prior to doing that I would have determined where the compression was leaking from. Through the intake, you have a valve issue. Through the valve covers, you have a ring issue ect... Along with the rings, I would make sure the heads are still true. Excessive heat can warp heads to the point that they will not seal.

Did you by chance do a compression check on all of the cylinders? What numbers did you get? Typically a wrapped head will show itself on more than one cylinder but stranger things have happened...

 

nope, no synthetic, i'll give this a try first since its easy and harmless, thanks!

 

i did check all of the cylinders, all were the same but #2 was a dead dog, i forget the reading, i have it written down here somewhere and it matched up with what others were sayiong was generally good

 

all check out on compression at +/- 2 of 135

 

Heads are straight and true, just checked. Guess I will be pulling the bottom to check the rings. Any advice for that?

 

Grab a new engine with a warranty from the pull-a-part on Patterson Ave. 3.1's a plenty and no rebuild cost

For a common V6/V8, replacement is the cheapest route when you get bottom end problems

 

yeah use this as an excuse to drop in a 350 or 383 in there...

 

good idea, and thanks! too bad i am in texas right now he heh

 

If you're willing to go to a bit of added expense and effort, I agree with this entirely. Will need to change fuel system and a buncha other stuff, but hey, you're pulling the motor already...

 

If one cylinder had a compression issue and all of the other cylinders were ok it really points to a head issue. I'd be very careful in inspecting the valves and combustion chamber of the cylinder in question. If you don't find any issues on the bottom end, get the head magnufluxed.