[urq] URQ loud "whistle" revealed!

[DGraber460 at aol.com]

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[ Picked text/plain from multipart/alternative ]
In a message dated 10/29/2001 2:23:57 PM Mountain Standard Time,
Steven.Buchholz at kla-tencor.com writes:


> ... the fact that it is a whistle sound and that idle appears to be affected
> makes me wonder if perhaps you haven't popped your idle air bypass screw in
> the throttle body ... probably something else whistling, but that's one that
> can happen ...

Right idea and very close.
This AM I finally was able to get the whistle at idle by blipping the
throttle.
Its coming from the lower rear valve cover gasket. I checked the injectors
which have new inserts, and seals in the last few months. All are secure &
tight. My stethescope proved the gasket whistles when the crankcase
pressurizes. If I pull the dipstick it immediately stops.
When I put this motor together last summer, I used the better rubber gasket,
and all the cover nuts are tight. Evidently, when I freed up the airflow
through the cat, the boost increased enough to blow the gasket. That also
explains the effect on idle.
VERY strange (and frustrating till now)! I don't mind problems so much when I
can figure out how to fix them.
The large hose from the igloo connects to the cam cover, joining another hose
from the back of the IM. Is there supposed to be a check valve or anything in
this connection? Seems odd to have full boost manifold pressure going into
the crankcase. That would also pressurize the intake hoses?
All input/responses appreciated.

Dennis