I think your mechanic was trying to avoid a trip or call to the parts store.
Both the Castrol GTX 10W-40 and 20W-50 are turbo approved unless he has some
real old stock.  The only difference between these two oils is the
viscosity, and yes, you should use the 20W-50.  For where you live, the
10W-30 or 10W-40 should only used during the winter months.

Dennis
-----Original Message-----
From: Maureen Stretch <mstretch@SPRINTMAIL.COM>
To: Vanagon@VANAGON.COM <Vanagon@VANAGON.COM>
Date: Thursday, July 30, 1998 11:42 AM
Subject: 10W40 �Turbo-proved� v. 20W 50

Dear Listees,

Yesterday I took my Vanagon in  to get the oil plug drain rethreaded for a
larger plug. That went fine, but the mechanic prefers to put 10W40 Castrol
GTX oil in instead of the 20W50.

(This is the mechanic that does not know a lot about Vanagons. I figured he
was right for the rethread, because he has done it for Volvos and other
cars, and agreed with most on the list this was a better way to go over a
Heli-coil, if it could be done. )

I said the VW manual recommends 20W50 for my 91 GL Westy, in temperatures
above 70, and so does everything I have seen on the list. I use the A/C in
summer and now tow a small, 3x3 foot trailer that weighs about 600 pounds.
Here in the Northeast it has been in the 70�s, 80�s and 90�s lately, but not
blistering hot as in the rest of the country.

He says the Castrol GTX 10W40 turbo-proved is just as good if not better,
for summer, because it is designed for turbo engines which run hotter and so
it is not likely to break down. The reason for the 50W he says is to prevent
the oil from breaking down.

While I love my Vanagon dearly (tomorrow will be our 1-year anniversary
together!), it has sure been an education in mechanic-speak and dealertalk.
Is he right? Is 10W40 Castrol GTX turbo-proved or proof the same as 20W50
for the Vanagon? Or should I just insist on 20W50?

TIA

Maureen Stretch
Natick, Mass.
91 Vanagon GL Westy �Johann�