"bob" > wrote in :

> Had a Intake manifold leak on my 96 Chevy Pickup with 5.7L. Leaking
> from passenger side front. Thanks for all of the help on this so far!
> When I pulled the intake, I was surprised to see the 2 intake ports
> on the front of the motor on passenger side (2 and 4 maybe, can't
> remember how Chevy counts cylinders) had a thich goooy black tar like
> coating up to 1/8 thick maybe choking down the ports. Felt gritty and
> had to dig out with screw driver. Is this what happens when the
> Dex-cool comes in contact with gasoline? What would cause this? Also
> had some black chunky stuff stuck in the valley between lifters. The
> stuff was hard and gritty. Felt like clumps of sand with oil. There
> wasn't much of this but I have been using Mobile 1 since the truck
> had ~20K miles (now has 136K) and was surprised to find goo and chunky
> stuff in the motor. I am using K&N filter but will probably go back
> to paper.....
>
> Thanks again for any input. Just curious what would cause the goo in
> the ports and the gritty stuff in the lifter valley.
>
> bb
>
>
>

Goo in the ports....blowby from the rings goes into the crankcase, which
in turn is routed through the PCV (positive crankcase ventilation), back
into the intake tract (usually the breather...but I have seen them go
directly to the intake). Does the PCV valve happen to route into the
intake near the ports in question? The vent gases from the PCV, if
excessive, will usually be oil laden.

The crusty junk under the intake... the conclusion I have often come to
is, it appears to be baked oil/contaminants. Motor been hot?




--
Anthony

You can't 'idiot proof' anything....every time you try, they just make
better idiots.

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