> I don't know what "too hot" is where oil is concerned, but 220 F under
> heavy load does not sound very hot to me.  I'd think that's surely
> within the limits of any good conventional oil, to say nothing of
> a synthetic such as Mobil 1.

Well yeah, 220F is certainly a perfectly reasonable temperature, but
It's also probably a highly optimistic reading. It's a long run to the
sensor, and the sensor is in the oil drain plug, which sits on the
coolest oil in the whole engine. The real internal oil temp is
probably 10 degrees hotter, and the engine is hot enough to boil my
coolant when I shut it off. It's not a heavy, rolling boil (except the
one time I was at 9000ft altitude), but it's a pretty good burble up
to the pressure tank, and my oil pressure is under 10psi at idle. Even
if it's within limits, it's still better if the oil temperature can be
kept consistent. I do use synthetic oil, and the oil can surely handle
the heat, but the closer you can keep an engine to ideal operating
temperature (somewhere from 180-200, depending on who you ask) the
better.

> This is what I am always afraid of when I'm tempted to "outsmart" the
> professional automotive engineers who designed the stock system.

Well.... as I've noted before, there's a heck of a lot about Vanagon
engineering that demands "outsmarting".

--
John Bange
'90 Vanagon - "Lastwagen"
'90 Vanagon GL - "Wiesel"