View Full Version : Thermostat?

05-14-2015, 05:41 PM
I removed my surge tank to have it repaired, prior to doing this I ordered a new gasket & 180 degree thermostat. The thermostatthat is on it is 160 Degree. I know the manual says it should be 180. To date I have had no overheating issues and wanted to know if I swap in the 180 degree one whether it will cause any problems.

Thanks Eric

05-14-2015, 07:06 PM
The answer depends on the health of your other components.
Does your heat riser valve move freely or is it stuck shut? It is located on the passenger side of your exhaust manifold.

Does your radiator have good flow with only a few cores blocked?

Does your water pump flow well?

Do your rear cylinders get adequate coolant flow? This question points to your head gaskets and whether the cooling holes are proper size or if they have rusted through.

Your engine came with a 180 degree thermostat. It should have one now unless someone thought a lower thermostat would get a jump on an overheating problem.

There are other factors involved, like air flow through your radiator. So, your question depends on the condition of your 50 yr-old system. - Dave

Dakota Boy
05-14-2015, 07:42 PM
I have always wondered why thermostats with different temps are available?

180 F seems to be the most "common" one that is used.

05-14-2015, 09:22 PM
Assuming your cooling system is in good shape, the thermostat will control the operating temperature under normal conditions. The thermostat temperature rating is where the thermostat should start to open. The water flow rate through the system is controlled by the diameter of the opening of the thermostat. Yes, the thermostat actually acts like an orifice in the system to control flow. If the water flow through the system is to fast, there is not enough dwell time in the radiator for proper cooling. That is why in the olden days, guys would pull the thermostat when their cooling systems were plugged.
Why the different temperatures? The hotter you can run a cooling system or engine, the better the efficiency and hence fuel mileage. Also, the engine will actually run cleaner and have less wear at higher operating temperatures. Of course, this is within reasonable numbers.
Since our Squarebirds have a history of running hot, a 160F thermostat probably won't hurt you, especially in California. If you are in Minnesota, and you want a good heater in the winter, I would opt for the 180F.
Many of the new cars now have 195F thermostats to help with efficiency and fuel mileage.