Quote:
Originally Posted by dporto
"By starting from a lower minimum temp, and returning to it when air flow over the cooling system allows, both coolant and oil temperature's are reduced, and any inherent "hot spots" caused by the mechanical design of the engine castings are running cooler."
Ah... So you're saying that due to the T-stat opening at 160 degrees, the block and oil temps NEVER reach the higher temps that they would reach with the 180 degree t-stat - therefore lowering the overall operating temp. of the motor ? This seems to make sense - much more so, than the T-stat "controlling" the coolant temperature. Thanks for the reply 
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"... NEVER reach the higher temps that they would reach with the 180 degree t-stat ..."
Not so. Although the thermostat sets the minimum operating temperature, the actual operating temperature is a function of the thermal efficiency of your cooling system.
Might the somewhat divergent opinions be summarized as follows?
- Cooler operating temperatures is likely to minimize head cracking.
- Cooler operating temperatures is likely to result in improved performance.
- Cooler operating temperatures will decrease heater efficiency. Yes, I know, but in some regions this is important.
- The minimum operating temperature is established by the thermostat.
- The actual operating temperature is a function of the thermal efficiency of the vehicle's cooling system. Above the constraint of thermostat temperature, as per above.
- To achieve a significantly lower operating temperature, a lower temperature thermostat may be insufficient by itself.
- Utilizing a lower temperature sensor to activate the radiator fans may reduce operating temperatures particularly in low speed applications, e.g. traffic.
- Utilizing a bypass switch to activate the radiator fans may be desirable in performance applications.
- The use of a third (center) radiator will improve the thermal efficiency of the cooling system.
- If your temperature gauge is acting 'like an idiot light' it is likely that you have a problem in the sensor, gauge, or wiring that needs to be remedied. In my experience, these are reliable and yield repeatable results. Granted it is a single location measurement but this measure can be read with confidence.
I return to my original statement - before investing in a low temp (i.e. 160F v. 185ish) thermostat, remove your thermostat and see how much (or little) the operating temperature falls. Then you can make an informed decision as to how to best invest your funds.
BTW, I am running a 160F Motorad thermostat sourced from Pelican and I see a typical operating system reduction (Interstate speeds) of maybe 10deg off the stock thermostat. When participating in a track event, there is no change in peak operating temperature at all from the stock thermostat - both run about 200F. It may be my imagination, but I believe I see a slight increase in fuel economy as well - maybe an additional 1 mpg.