Huw Powell human747 at
Fri Aug 9 17:00:06 EDT 2002

> > it's not the head that heats the oil to 150 C, it's the two *really* hot
> > places it goes, which are the turbo and the backs of the pistons.  Of
> > course the turbo is also water cooled, so it is not such a factor.
> > However, the oil sprayed on the pistons gets some serious exposure to
> > heat, and then *is not* water cooled before passing the temp sender.
> yes, that's true.  and plus the specific heat of water is so damn high
> that I can buy that you wouldn't see violent swings in the coolant
> temps.. but eventually a 150c oil temp HAS to transfer some heat energy
> to the coolant.

It does.  But follow the oil flow for a second here.

The very hot oil from the back of the pistons falls back into the pan -
no water cooling there.  Next stop, the oil pickup, then the pump, and
the oil temp sender.  The oil has not yet given up its extra heat to the

Finally it gets pumped around the block, head, and everywhere else,
where it can drop some heat, via the metal which is hotter?  into the
water.  Are there any places in the flow pattern that could truly be
considered oil to water heat exchangers?

Huw Powell

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