There really should not be a problem with the 5w-40. This is still a fairly
high viscosity oil. As a heavy duty Diesel oil it may have more ash and zinc
for acid control and and wear protection. These additives are know to reduce
catalytic converter life. That is why many oils are now either gasoline or
Diesel rated.

Dennis

>From: Michael Diehr <md03@XOCHI.COM>
>Reply-To: Michael Diehr <md03@XOCHI.COM>
>To: vanagon@GERRY.VANAGON.COM
>Subject: Mobil 1 Turbo Diesel Truck 5w40 in a Wasserboxer?
>Date: Fri, 13 Apr 2007 15:02:59 -0700
>
>I bought a bunch of Mobil 1 TDT 5w40 oil for my TDI beetle, and am
>wondering if it'd be a decent oil to use in a Vanagon wasserboxer
>(about 10k on a rebuild, doesn't burn much oil).  I used to use Mobil
>1 synthetic 15w50 in the old engine and liked it.    It would be
>easier to just buy a single oil....  anyone think the TDT 5w40 would
>be too thin?