Cooler Thermostats ?

[sixshooter]

Hey,

Just a few questions regarding cooler thermostats in L67 motors.

From my mechanical training years ago... my understanding of the thermostats purpose is to keep the coolant in the radiator long enough to be cooled down sufficiently before being circulated back inside the block. If you take the thermostat out of a motor, the motor will take along time to reach operating temp and then start to overheat.

So what effects do using cooler themostats have on the normal operating temp range ?

Do they make warmups take longer ?

Is the normal operating temp range reduced ?

What is the lowest opening temp that can be run ?

Do they cause overheating in hot weather ?

TIA

[Don Sutton]

A cooler thermostat only will cause the engine to run cooler but will use more fuel (depending on how cool). You may get more blowby gases contaminating the oil since the pistons will be washed with more petrol. Notice operative word 'may'.
The engine will warm to the new operating temperature quicker if you change to a lower range thermostat since it does not have to heat the water as much. If you have a problem with overheating then a lower temperature thermostat will NOT cure this. Why?
The cooling of an engine is the ratio of heat developed to the ratio of heat dissipated.
General stuff.
If the radiator is blocked less water flows through it so it does not dissipate as much heat.
If the water pump is buggered then less water will flow through the radiator.
If the engine is running lean then you will use a wider throttle opening to maintain power and more heat will be generated.
If the ignition timing is out (on modern engines with ECU control this would represent a faulty sensor) then a wider throttle opening will cause more heat generation in the coolant.
If you have a leaking cyl head gasket then high temp gases will enter te cooling system but this will more likely blow the coolant out of the system than actually boil it.
No thermostat will cause the engine to run cool for a long time but the temperature will keep on rising and may eventually boil because the water flows through the radiator too fast to have any time to dissipate the temperature.
The electric fan switch in is often about 5 degrees hotter than the thermostat temperature. Some vehicles (commodore included) either have an overide which switches the electric fan on when the A/C is switched on or an extra fan. This is because of the extra temperature of air flowing over the radiator from the A/C heat exchanger/condensor mounted in front of the radiator.

[sixshooter]

Thanks for your reply Don !