I think he's talking about that sound from the exhaust.
I'm going to guess that it has back pressure in the exhaust that releases
and the tail pipes (chrome tips) with the perforations inside tend to
whistle from this slight surge in pressure.

Stan Wilder

On Sat, 2 Feb 2002 19:43:02 -0800 Patrick Harris
<harrisvanagon@HOTMAIL.COM> writes:
> Now, I've been rebuilding VW motors since I've been 15 years old.  My
> 3 year
> old son asked me the other day when my buddy came over with his bug
> a
> question that I stood and was bewildered on.  He asked, "What makes
> it
> chirp?"  I stood there with a stupid look on my face and didn't know
> what to
> say.  I took the quick exit and said that "They're just that way".
> So, I
> ask everyone because I'm not sure... What makes it chirp?  I've
> heard
> exhaust, valves, heads, muffler, bad muffler...etc.  Anyone can give
> me an
> idea?
>
> Thanks!!!
>
> Patrick Harris
> Longview, Washington
> 1981 Vanagon (Project "Bessie")
> 1987 Vanagon GL
>
>
>
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