John,
I fear that boiling antifreeze is a sign of more than hot oil.  Where does
the coolant temperature gauge needle sit during all of this?  Just a WAG but
I thing you might have a failing water pump allowing hotspots to form in the
engine.  Possibly the radiator is on it's way out also.
Ken Lewis
http://neksiwel.20m.com/
in statu viae
----- Original Message -----
From: "John Bange" <jbange@GMAIL.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Tuesday, February 10, 2009 11:42 PM
Subject: Re: [VANAGON] Mocal sandwich plate plus oil cooler equals
overcooling

>> 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"
>