Experience using an in-line thermostat?

Some people are never happy... So I had my radiator re-cored late last year and I took the car ('25 touring) out for a brisk ride this afternoon. The Motometer didn't even register and the core was warm at the top but not so you couldn't keep your hand on it. Even the head was not too hot for the hand test. I think it was maybe 55 F ambient. Should I worry that it's running to cold? Resto Supply sells in-line T-stats that fit inside upper radiator hose (160 F). Anyone have experience using one of these? I know there were (period) aftermarket radiator louvers available for cool weather operation but I really wouldn't want to go that route...

Go to Horrible Freight and buy a $30 infrared thermometer and stop guessing how warm it is. But test it first, mine is off about 7 degrees because it's junk just like everything they sell.

I have one of those but I always forget that I have it... You do need to be careful about what you buy at HF, that's for sure.

I have used an in line for years in my 34 Dodge. It worked fine for me. I replaced it when I finally found the correct factory one.

Ken

Thanks Ken. I think I'm going to give it a try. Any idea where 160 shows up on the Motometer?

I have used an in line for years in my 34 Dodge. It worked fine for me. I replaced it when I finally found the correct factory one.

Ken

I couldn't find anything that showed specific temperatures for the Motometer so I did a little experiment today. I used my (reproduction) Motometer to get an idea what temperatures show up at what marks on the gauge. Here's a little cartoon of what I found. I used a hot plate to heat a coffee can full of water and used a thermocouple on my Fluke meter to read the water temperature. The Motometer is mounted in a dog bone which I rested across the top of the can with the sensing bulb immersed about 1/2 inch in the water. I know it doesn't sit in the water when in the radiator but I don't think there is much difference between water temperature and water vapor temperature inside the small volume of the neck. I find it interesting that on the gauge face it says "Operate in circle for high efficiency" (or something close to that) but the bottom of that circle is right about the 200 F mark. At the center of the small circle it will probably be boiling (I didn't test that high). Am I mistaken that we wouldn't want these 4 cylinder Dodge engines to run that close to boiling?

Test after test after test proved engines perform best at 195º.

I doubt my '25 Dodge would overheat in the Sahara and I think sticking a 190-195º thermostat in it would be a good idea since it has forced circulation and huge radiator.

My '27 Model T Tudor was overheating and rather than throw $700-800 at a new radiator at it I put on a water pump after which it ran too cold so I added a 180º thermostat (because the choices are 160º or 180º as the T cooling system pretty much sucks).

End of problem.......

The one for the T comes with a gasket that is marginally thicker than the thermostat flange so it's shoe-in installation between the head and water outlet flange.

Thanks. I know that 'modern' engines, with pressurized cooling systems run at 195+ but I thought pre-emissions reg engines typically ran with 180 F thermostats. I'm going to try out the 160 F and see how it goes when summer temperatures get here. Without anything in there and these spring temperatures I'm never seeing the red on the meter so 160 should be a lot better for the engine...