Fordnatics List Archive

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Mail From: chucko (Chuck Fry)

160 degree thermostats are a mistake, especially for computer controlled
cars.

The main reason is mechanical. Oil really needs to be warm, in excess
of 200 degrees F, to lubricate effectively. Lower than this and you get
excess drag. And it should reach at least the boiling point of water,
212 degrees, on a regular basis, so that the condensation from cold
running has a chance to boil off. Cold oil will cause sludge to form.

If 160 degree thermostats really made more power, you'd see them on pro
race cars. Ask any racer and you'll find engines make more power with
180 or 195 degree thermostats.

If you're trying to fool the computer into running a little richer, you
can substitute a resistor of the appropriate value for the Engine
Coolant Temperature sensor. That way the engine can run whatever
thermostat you want, and the computer still thinks the engine is cool.
A better idea is to fix the fuel curve directly, via an adjustable fuel
pressure regulator or a computer gadget like Crane's Interceptor II.

If you're using a colder thermostat to prevent overheating, you ought to
fix the real problem with the cooling system! Substituting a colder
T-stat does nothing to address the lack of heat capacity in the cooling
system. In fact, the cooler water carries *less* heat away. The only
benefit is that the T-stat opens sooner, but without solving the real
problem, you'll still overheat.

My rationale for using a 180 degree thermostat in my '89 Mustang (stock
is 195) is that I have the extra cooling capacity already, and the car
has a tendency to ping when it gets warm. I am hoping the cooler
thermostat will give me enough slack to prevent the ping, and enough
headroom that the car will stay cool at the track.

-- Chuck