[Vwdiesel] Thermostat temps

James Hansen jhsg at sasktel.net
Mon Feb 5 12:31:06 EST 2007

Within limits William.
Your oil doesn't care to run hot either.
bearing temps are supposed to be around 170C (approaching lubrication
failure)when the oil temp is 125-130C.  Normal operating temps for
engine oil are considered to be 65-90... in fact wear has been shown to
accelerate when the oil temperatures are below 60C, hence the wisdom of
what a vast majority of diesels have- an oil to water "oil cooler",
which serves as much benefit in warming the cold oil after starting, as
it does in keeping the oil cool.
It would be an interesting experiment to begin with a fresh motor, and
run waterless coolant with a thermostatic water to oil cooler to warm
the oil from cold starts, and another oil to air cooler to maintain the
max oil temp at safe levels, while running a 240 degree thermostat and
waterless coolant.

You would have valvespring issues eventually with stock springs I would 
think, but I wonder what the overall efficiency effects would be, and if 
you could ever recover your additional costs.

William J Toensing wrote:
> I don't know if this is true, but I recall hearing back when I owned
> my German built (European delivery) Rabbit diesel that VW ran  40
> pound PSI in the diesel & this was responsible for early radiator &
> heater core failures due to metal fatigue from continual expansion &
> contraction. If so, this would be a great argument for running Evans
> coolant. Thanks to this discussion group, this is the first I I have
> ever heard of Evans coolant & its high boiling leval. Its my
> understanding that engines will run better & get better MPG if they
> run hot, as long as they don't overheat. If you run an engine at ,
> say 300 degrees F, I wonder if some other part of the engine might
> fail, even though synthetic oil & coolant allow the higher
> temperatures?  I lost two engines ( 1972 Citroen gas engine & Mazda
> 626 diesel) which overheated & DID NOT seeze, due to use of Amsoil
> synthetic, but got so hot the valve springs lost their temper & the
> block overheated (Citroen). 
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