Think of it this way -- does it really make any sense to suppose that
a thermostat will make the engine run warmer in winter by
restricting flow and will also make the engine run cooler in summer by
restricting flow?
In the Tiger owners manual it says to use a 160F thermostat in the summer
and a 190F in the winter. The thermostat opens at a lower temp. in the summer
to allow coolant to flow from hot engine to cool radiator sooner thus keeping
engine temp lower. A higher temp thermostat in winter allows hot engine coolant
to reach a higher temp before reaching much cooler radiator thus making the
engine warmer in winter. In either case, coolant flow is restricted at
different temperatures to achieve the opposite results cited in your question.
Or am I totally wrong?
Keepin' cool,
Jeff
______________________________ Reply Separator _________________________________
Subject: Re: Radiator cleaner
Author: "W. R. Gibbons" <gibbons@northpole.med.uvm.edu> at INTERNET
Date: 6/11/97 2:03 PM
On Wed, 4 Jun 1997, Michael Fisher wrote:
> BTW, removing the thermostat actually increases coolant temperature vice
> decreasing it. This is a somewhat complicated fluid flow problem but the
basic
> deal is the radiator cools by convection (temperature difference to 5/4 power)
> and the engine heats by conduction (difference in temperatures). So the
> radiator is a more efficient cooler than the engine is a heater (provided the
> radiator and fan system is in good shape!) Removing the thermostat means a
> constant flow system and consequently the radiator has no time to remove the
> heat in the coolant before sending it back to the engine. End result is
> coolant temperature rises. This can be somewhat mitigated by ambient
This issue has been flogged to death on other lists. It is conceivable
that removing the thermostat may lead to water pump cavitation, so that
flow actually decreases without the thermostat. Or possibly removing the
thermostat may alter the pattern of flow through the engine causing hot
spots. It is true the engine was designed for a thermostat and should
have one.
However, I respectfully disagree with the reasoning given in this post.
The idea that the water will move through the radiator too fast to lose
heat is, I believe, simply not correct.
The primary purpose of the thermostat is to regulate flow (by restricting
flow), so the engine runs warm enough (at the thermostat temperature). In
most cars, removing the thermostat is a poor idea because the engine will
run cooler than optimum.
W. R. Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8629
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