Mine does that too, when it's in the single numbers or < 0 Farenheit.

-----Original Message-----
From: harald_nancy <harald_nancy@EARTHLINK.NET>
To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Date: Friday, March 24, 2000 8:21 PM
Subject: Cow mooing in wasserboxer

>Just wondering if anyone knows this sound.
>Lately everytime I start up the van, and the engine
>is cold, it sounds like a cow mooing coming out of
>the engine compartment.
>Sort of like this. Moooooo.....
>It only does it at about 1500 rpms, and then after
>a few minutes it goes away.
>Maybe I should buy some hay.
>Harald
>'90 westy
>