Guys, the temp sensor is on the radiator side of the system. You'd need one on the engine'* lower hose to determine exit temp of the coolant, which isn't going to be any different.

As to running at 183 degrees, Will, it seems unlikely at best. It'* easy to tell. Let your car idle after a run and squeeze the upper radiator hose. If it'* solid, the system is pressurized-which means coolant temp is above boiling. And that'* prolly where it'* designed to be.

This is an academic discussion, to be sure. But I'd also say that Pontiac had a few powertrain engineers that spent a few bux to determine correct coolant temp.

(of course, these are the same guys that designed the UIM, so.... )

While a thermostat itself will not cool the motor, the cooler thermostat combined with lower fan points settings (to match the thermostat rating) will indeed keep the coolant cooler and thereby the motor.

The thermostat simply opens at its temperature setting. A car with stock fan points (205 and 215 (hi)) will not run cooler with a 180 t-stat only, as the car will heat up to the point the fans kick on (or high speed air cools the temps some) this is why cars in traffic run hotter than those on the move.

A car whose colder thermostat opens sooner and allows coolant to circulate earlier will run cooler on the highway than those with stock 195 thermostats.

Please explain your reasoning. This may happen initially, i.e., the first few moments of freeway driving, but it seems to me that once the thermostat is open, it'* really not a part of the operating temperature equation any more.

Because the cooling capabilities of our cooling system can easily lower coolant temps below a stock 195 thermostat. The 195 holds coolant in the motor until 195 degees and then opens the coolant flow allowing the system to cool it down. If you open it at 180 or even 160 the coolant is allowed to circulate and cool to the systems max capacity for cooling or whenever its capped by the specific thermostat. If you run without a thermostat for example my car keeps coolant at about 140. While this is not ideal for mileage it does allow you to run more timing and boost without getting KR from excessive cylinder heat.

This isnt to say that the system will always be at that temp. During Hi speed WOT runs such as the 1/4 mile my system with a 160 will heat up to 180 during the run but then cool down as soon as I get out of the throttle. But during cruise or in town driving my temps are always at 160ish.

Man your a curious one aint ya,,sounds like you don't know the first thing about a
cooling system,,,do a google serch and get educated man!!!!

I agree 100% with Rogue'* statment;

Would it be fair to say them, as your coolant temp is always below boiling, that the system never pressurizes, i.e., exceeds the boiling point of coolant (i.e., around 212?)

It is important to point out, as well, that the thermostat itself is a partial restriction to coolant flow. The traditional Pontiac V-8, for example, will promptly overheat without a thermostat in place, because transit time of the coolant through the radiator is reduced greatly. We remove the thermostat for the drag strip, but also have a restrictor plate in place of the thermostat to slow transit time.

Rogue, the coolant temp must fluctuate, because if your coolant temp remained at 160 around town with a 180 thermostat, it would mean that no coolant was flowing through the radiator, right, as a 180 thermostat is closed at coolant temps of 160?

[quote="daman"]Thanks for your scintillating and erudite comments. You add much to this discussion between friends.

[quote="Bob Dillon"]We'll.......listen to what your friends telling ya!!!!!!!!!!!!!