what is the difference between these two thermostats

Andre (NE) · May 7, 2009

So, I want to replace the 180 thermostat in my M with a 160 which is what should be in there in the first place.

But, which thermostat should I get:

or

what is the difference (other than the physical appearance)?

My M is the "early" M.

Bob · May 7, 2009

Many of us tractor guys think a 180º thermostat is just fine for old tractors. One of the reasons for the cooler thermostats in the "old days" was not to boil away the alcohol-based anti-freeze, no longer a problem.

Warmer engine temps = less oil contamination.

Underwood · May 7, 2009

Andre, I just bought one from CIH for a "49 M that looks like the one in your top illustration. My question is this, the "housing" around the temperature sensing button (on the right in your illustration) was stamped with an arrow and the words "To Rad" that indicated the housing with button should be on top, up in the pipe going to the radiator rather than down, on the engine side like every other thermostat I have ever seen. Thats the way I installed it but what is the board"s opinion, is this correct?

ET · May 7, 2009

The lower one looks like what I put in a UD236 engine. The themostat opens two passages when it opens. One is the top disk in the thermostat and the lower disk opens another passage where it sets against the cast housing.

Anonymous-0 · May 7, 2009

The top one in the picture is type for H, M etc. If you can find a 160 I would have no problem with that however a 180 is more in line with todays thinking. At any rate, the one in the lower view is not going to allow the bypass recirculating feature in these engines to operate. In the early 80's, IH mistakenly listed the wrong style thermostat for these tractors and did a recall on them. I will add that some of the old housings get so rusted out that the coolant can go right on past the tube on thermostat and engine will not warm up under no load. I had a machine shop install a seal much like the 66 series tractors use, but can't remember if this was on a 450 gas or diesel. I have couple of H tractors and one is letting coolant just fly on by the thermostat and never warms up with the little dinking around I use it for, so , one of these days I will have to tear into it. I should have stuck a garden hose in the housing while I had it apart last year but I though it would be ok.

Bob · May 7, 2009

GOOD answer, Pete!

Evan Shockey · May 7, 2009

Warmer also means less fuel used, in theory of course!

Bob S. · May 7, 2009

Andre
Go with original equipment and temp recommended in owners manual (or wherever it shows up, I didn't look it up). You can run it hotter But running it hotter than recommended can cause problems. They did have engineers when they built these tractors and they knew what the cooling systems were designed for. It's not just a matter of running it hotter to get better performance and fuel economey, overheating it in the middle of a work day is not too economical. Like I said they did have engineers 50 60 years ago and even though they had to use slide rules they knew how much coolant would flow under load and what the boiling point of various coolants was according to radiator pressure etc. If you were running a race car down the drag strip, good and hot for 8.5 seconds would be great, but not if you are going to run an old tractor for hours on end. Only my two cents worth, good luck.
Bob S.

Bob · May 7, 2009

Bob S. · May 7, 2009

Alcohol thermo was 170 degrees
Bob S.

what is the difference between these two thermostats

Andre (NE)

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Bob

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Underwood

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ET

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Anonymous-0

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Bob

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Evan Shockey

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Bob S.

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Bob

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