92 Ford F150 - possible blown head gasket

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 (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?

Reply to
mjtobler
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Either one. A machinist can either use a dye or an X-ray to tell you if there is a hairline crack that you're missing.

If it were my car, I'd drop a new gasket on it, clean the gunk out, and see if that does it. My time and a new gasket costs less than the machinist.

--scott

Reply to
Scott Dorsey

Usually if the head gasket is blown. the affected cylinder will be a 'lot' cleaner than the rest, same for the sparkplug. Did one plug look like new?

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail > Once again - 1992 Ford F150 5.0L 302 V8 175k miles, auto.
Reply to
Mike Romain

Thanks for the reply, Mike. That's a good question concerning the spark plugs/cylinder and makes perfect sense. We'll have to check those two out. Probably take some photos too (to post).

Reply to
mjtobler

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