harald.nancy wrote:

> Steven X. Schwenk theorized:
> >
> > Is this an old already rejected theory?  Wouldn't running the engine say
> > 10% cooler...or any cooler than stock set up, have some adverse
> > consequences?
>
> I replaced my 87c thermo on my '90 vanagon with a 80c degree
> thermostat. I haven't noticed any adverse affects. Does not make
> very much of a difference, except during freeway cruising, temp needle
> stays a bit lower than it used to.
> Oil temperature seems to stay a bit lower too. Fuel mileage is the same.
> In stop and go traffic, temp rises until fan goes on, as before.

 Running a cooler temp thermostat can work against you. Remember, the entire
Digifant system is reliant upon 195 deg F water temp for proper (ops normal)
feedback to the ECU. Anything lower than this and the ECU would try to
compensate by for instance changing ignition timing to achieve the desired or
anticipated O2 temp.
Now there should be some window of float that are acceptable to the ECU, I
don't know what those are, but I would be careful changing thermostat temp
ratings in any Electronic Fuel Injected engine, for it has a potential to
introduce a "feedback mechanism" of correction back to what the ECU knows to
be the norm.
Additionally, lowering coolant temps and pressures would have little bearing
on the head gasket issue. The issue is the corrosion, not pressure. And the
pressure comes from the other side in a failure, that is the combustion side.
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Shalom
Mark B. Magee
82 Diesel Westy
87GL
91 Westy
96 Suzuki 4WD Sport
Kemah TX USA
John 14:6