RE: bmw-digest V9 #576

["Legerlotz, Alan" <alegerlotz@xxxxxxxxxx>]

>>	Did the frequency of your tapping change with engine RPM?
>>	About 50% of RPM?  Did it start about 10 seconds after engine
start-up?
>>	Did it stop sometimes after about a minute, sometimes longer?  Did
it
>>	sometimes not happen at all?  If so, you may have identified a
problem
>>	that I've had with my M50TU from new to now (51K miles).

Yes to all of the above.  I was actually worried that it was a "rod knock"
or something because it sounded a bit too low in audio frequency (not
volume) and was tapping too slowly and too distinctly to be what lifter or
valve noise sounds like to me.

When I called the mechanic we ruled out rod knock almost immediately because
that's more typical at an idle speed with the engine (and oil) warm.  The
mechanic wasn't sure what it was, but was pretty certain that I shouldn't
worry about it.  A couple of days later, they had another 328 at his shop
that was ice cold in the morning.  On startup it was tapping just as I
described.  He did some quick checking and even looked something up and it
was the EGR valve as I described yesterday.

If you're wondering where its located, its on the passenger side of the
engine, just above the exhaust manifold,  around cylinder 2.  If your car is
making the tapping noise, you can try to listen in different areas, and I'm
pretty certain that the sound will be greatest around that valve.

- -Al
1996 328is 
1990 735i

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