Once again - 1992 Ford F150 5.0L 302 V8 175k miles, auto.
A mechanic determined there's a blown head gasket.
Following behind the truck, you could see "steam"
coming out the exhaust and the truck ran roughly.


Upon disassembly of the manifold and heads, we see:
* the inside of valve covers are coated in brown goop,
which is obviously water mixed with oil
* the rear of the lifter valley has the same muck
* the underside of the (lower) intake manifold, at the rear,
is coated with the same brown goop.


Cylinder 3 (I could be wrong - it's the 3rd cyl back from
the front on the passenger side) has, what appears to
be either "a build up of something" or scoring from the
piston. Looking at it, you want to rub your hand on the
surface to rub off whatever it is, but it wont.


Anyway, so here's the strange part - examining the head
gaskets, there is no visible sign of a "break" or "blown"
pathway. Examining the "impressions" on the head and
the block from the gasket rings (the "ring" impressions), there
is no evidence of water traveling to a piston bore/etc.


Any ideas what this could possibly be? Could there be
a hairline crack in the block or head or intake manifold?
Or could there be a hairline tear in the gasket that is not
visible to the naked eye?

 

Do you have your cat on still? check to see if it is plugged check the muffler too I had this happen with a 91 blew out the intake gaskets

good luck

 

When you say, "had this happen", what are you referring to? Did you
have the same symptoms? Yes, the cat and muffler are still there and
I agree that the cat could possibly need replacement. The problem
first reared its ugly head on the freeway and there was a loss of power
and the engine temp rose about 3/4 up the gauge. (Normally the gauge
is around the 1/4 mark or less).

Are you suggesting that because of a defective cat, which would cause
excessive back-pressure, that it could potentially "blow" the intake gasket?
Would this cause the obvious water in the oil? Also, what about the
apparent "steam" out the exhaust?

Sorry for all the questions, but it is all a bit perplexing.

 

YES it would and yes my symptoms were the same

 

not sure how a clogged cat would cause the intake gasket to blow. But I could see where a blown intake gasket would clog a cat from sucking in oil and burning it.... if you got the heads off get them magnafluxed, could be cracked somewhere... Not sure what you talking about in the #3 hole... but if the cylinder is all scored up it may be time for a rebuild. Take pics...

 

I'm a bit perplexed, too, how a clogged cat could blow an intake gasket, but
I have seen some strange things with vehicles. My own direct experience
with a clogged cat: sudden increase in engine temperature and an incredible
loss of power (gas pedal to floor, no power).

So it sounds as if there is the distinct possibility of a hairline crack in the
head(s), the block (or worse, both) or possibly the intake gasket is blown.
I can imagine if the intake gasket is blown between a water jacket and
the lifter valley, coolant will drain into the lifter valley/oil pan, but how
would we be seeing "steam" out the exhaust, obviously being combusted?

Any others out there have other ideas or similar experiences?