Thread: Diag help Needed on a head gasket leak

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Help!
I tore the engine down and did not find the obvious cause...so here is the details:

Been losing coolant, but engine has been running fine, no other symptoms (gas mileage is fine, no smoke/steam or boiling over, etc).

replaced the O2 sensor 2 weeks ago, got the code for it, did it, all fine now.

Got a cooling system pressure tester, system would hold NO pressure - it would drop about as fast as i could pump it up...and AF ran out the tailpipe.....AH HAH! I found me thinks...

OK: Plugs look worn, but not steam cleaned.
Cyl heads look normal (not steam cleaned as one would think if AF was getting into the compustion chanber)
Gaskets: nothing obvious
Heads seem flat (i am NOT a machinist)
One cylinder had AF laying on top of the piston. all other holes were completely dry.
The head bolts on the suspect side did not seem as tight as those on the probably good side.

Engine: 96 Dodge 3.3 V6 in a Caravan. Iron block, alum heads, 115k miles. History before 90k unknown. The rear bank is suspect because of the AF running out the tailpipe so easily, that is where i found AF puddle on the piston, and the head bolts were not as tight.

QUESTIONS:
Should i clean and reassemble? The bolts 'should' be replaced, but dealer people tell me 'not unless they are stretched'...So perhaps new bolts and (of course) gaskets and put it back together?

Do i send the heads out...that will delay reassembly for several days and comst some amount of money, and probably mean new valve seals as well.

you said, The rear bank is suspect because of the AF running out the tailpipe so easily, that is where i found AF puddle on the piston, and the head bolts were not as tight. "but engine has been running fine".

those 2 statements dont belong on the same post. if you got AF running out of the tailpipe then you got a miss. if you got AF running out of you tailpipes i wouldnt put the heads back on until i found out where it came from. a crack in a alum. head would be a good place to look.

You seem to have answered your own question,,,,,the Cylinder head should be sent out for inspection,,,,dont even bother to re-assemble,,, at this stage you will create more frustration for your self,,and Damage your bottom end further.

There can be no bottom end damage as there is NO AF in the oil. None, zip zero. No frothing, no discoloration, nothing.

The engine was indeed running fine. the plugs (i can go take pics) are fine. the cyl head carboning is fine. the exh ports all look to be the same, carbon wise.

A few pumps on the pressure tester and green AF ran out (technically a hole in the muffler..) the exhaust. Based on how the exh manifods run it almost has/had t be the rear bank.

bathing an O2 sensor in AF steam would probably shorten it's life. I considered running a compression test, the rear plugs are a serious b*tch to get to.

For $80 I can get the heads checked...but that won't be done till wed at the soonest. It would have been nice to be able to have the van back for work on monday.

My jeep is not a great daily driver.