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How do I pressure test exhaust manifold

J

Jay Reed

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I was hoping someone could det

I was hoping someone could detail how to pressure test exhaust manifold/cooling system. I have water in crankcase. engine still seems to run fine/have good power. am I right to suspect exhaust manifold/gasket? then head or head gasket. cracked block. any other possibilities? I spent the last couple of days reading this board. its a great resource. thanks. -jay

1995 4.3 gen 2 drive (freshwater)
 
"First suspect: manifolds &amp

"First suspect: manifolds & risers
Second Suspect: head gasket
Third Suspect: Cracked block (if it froze, move this to #1)

You can remove the manifolds to test. Plug the inlet water fitting and fill with water. Look for any water leaking into the exhaust passages.

If they check out, plug the water outlet and inlet fittings at the T stat housing and pressure test the block. It should hold 10-15 psig for at least an hour.

How many hours on the engine?
I see its fresh water, which is usually easy on manifolds/risers.
Has it ever been overheated?

Rod"
 
"thanks rod
engine has about


"thanks rod
engine has about 900-1000 hours (meter stopped working a few years back at 703). engine did over heat earlier this year. suspected impeller even though it was only a year old, on inspection it was fine, mechanic replaced anyway, said there was some sort of blockage, (mouse nest?) that he got flushed out. no longer over heating but grey/milky oil... my first thought was head or head gasket. after reading here I guess I will try manifold/riser gasket. -jay"
 
"Maybe try pulling the plugs a

"Maybe try pulling the plugs and check them.
Water in the combustion chamber will make them very light, almost white. Could be a clue.

With that many hours it could easily be a head gasket, or manifolds.

Rod"
 
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