MTFCA Forum

I bought a new thermostat for my T from Snyder’s, and when it arrived I found that it doesn’t fit into the opening in the block very well, and it’s big enough in diameter that the bolts that hold the housing on hit the outer edge of the thermostat. Are there different sizes of thermostats, or is this how it’s supposed to be?

Rob

since a "T" never came with a thermostat, there is no drawing for a supplier to refer to or manufacture to...thus, something off the shelf at NAPA is used, and you get to make it fit.

Does your T really run too cold?

unless you have a waterpump, your car will not start circulating water to any degree until it's up to 170F or so, so it's useless on a stock "T". If you need a waterpump, it's because your radiator is pooped, and then perhaps the thermostat could be considered necessary.

I have 4 "T"s. All came with water pumps. All water pumps came off and then I had 2 "T"s that ran fine and 2 "T"s that overheated. Water pumps went back on those 2 cars...without thermostats and all 4 cars are happy.

Our valued suppliers sell things people want to buy and People will buy thermostats. Unfortunately, very few cars really need them.

Oh gotcha. I learned about model T engines in college, but it’s been long enough that I’ve forgotten some things.

Sounds good. I guess I’ll put it together without the thermostat in it. It didn’t have one in it before, so it’s probably okay.

I've found my 26 runs well with the 160 degree thermostat. Using an IR thermometer, temperature is consistent front to rear and my plugs in cylinder 1 and 2 run just as clean as in 3 and 4. I got my thermostat from Lang's and there was no interference in the fit to my Z head. Yes you can run a T without a thermostat, but I believe temperature control increases the efficiency of the engine.

I run thermostats in all of my T's and believe it it is a great upgrade (like an air filter). If I remember right a older small block Chevy thermostat will fit, make a gasket out of thick gasket material, you have to cut the gasket to go around the outer diameter of the thermostat and use a fair amount of silicone sealer, snug up the bolt and let the sealer set up and then tighten the bolts.

Thermostat and gasket are listed on this page. https://www.modeltford.com/item/A-TH60.aspx

A Model T WITHOUT a water pump has no need of a thermostat. If you add a water pump, for whatever reason, a thermostat is necessary, especially in cooler regions, to to assure quick, even warm-up and proper operating temperature.
The thermostat needs to have a I/8 to 3/16" bypass hole in it to allow some limited circulation during warm-up and to allow air to escape the water jacket when filling the system. On a T with a water pump, I'd use a 180 F thermostat. If your radiator is plugged up, that's another matter. The last thing a Model T with no water pump and a junk radiator needs is a thermostat. A T with a junk radiator needs the radiator repaired or replaced. If you live where hot weather is the norm or at high elevation and drive a TT truck, adding a water pump and thermostat is a sensible modification. If you pull any kind of trailer with a Model T, a water pump and thermostat make sense. I do not use a water pump in my '26 T roadster because it never overheats, even in 105F heat at 40+ MPH. With no water pump, no thermostat is needed. I have a clean Berg's flat tube radiator and I use the carburetor mixture control and the spark advance as needed for best performance. I have run the car both with and without a fan, and it runs the same temperature either way, BUT, with no fan, or no fan belt, the engine temperature will climb very rapidly when the engine is running and the car is standing still, especially in hot weather. With no fan, the engine runs a little hotter with a tailwind, but it has never overheated. The car has a modern temperature gauge with the sensor located at the water outlet. Since the system never boils, I don't worry about the temperature as long as it is 170 to 190F during normal operation.