Farmall Cub

I have a thermostat that came in one of several boxes of cub parts when I bought it 40 yours ago. It fits nicely in the coolant outlet. It is 170 degree with a part #377603R91. My parts book does not go past #356635R1. It looks like an IH part number to me.

I am thinking that I should install it and see how well it works. My Cub is very cold blooded, especially in the winter pushing snow. Covering the grill helps. I can monitor the temperature because I have a temp gauge with the sending unit in the side of the block. Only time it will read in the middle of the green is when I run the Woods 59 on a 90 degree day for an hour or so.

Thank,
Ted

....T M does not even list a questionable thermostat---

cubs do not use a thermostat, you have a system without a water pump, so you will just be blocking the flow

That part appears to have been sold in package 377602R91, which was that thermostat with a spacer 377604R91. It was used in the C-123 engine on the 56 balers.

I know Jim could find it.

Mike in Louisiana wrote:I know Jim could find it.

I thought he would also. I really appreciate his knowledge and his ability to find answers to our questions.

Jim is King of the part numbers.

Just started and ran the Cub after installing the thermostat. Temp started to warm up fairly quick and the needle went to the L on COLD, the 170 degree thermostat opened and the gauge went right down to C. I will keep an eye on it when I work it hard in hot weather.

In the green RUN section there is an arrow above the N. Does that have a meaning? Maybe ideal temp.

Thanks, Ted

tnestell wrote:In the green RUN section there is an arrow above the N. Does that have a meaning? Maybe ideal temp.

Thanks, Ted

Does it look like this one? I would guess the arrow indicates the nominal 'Run' temperature.

After some quick reading, that likely indicates the optimal temperature for running on distillate or kerosene. That style gauge was used on larger IH tractors that could be run on fuel other than gasoline. Here is an excerpt from the Farmall C manual:

Urbish wrote:After some quick reading, that likely indicates the optimal temperature for running on distillate or kerosene. That style gauge was used on larger IH tractors that could be run on fuel other than gasoline. Here is an excerpt from the Farmall C manual:

Thank You

Cut grass today with the grill covered because it was it was 55 degrees. Woods 59 in second gear and at 1800rpm. Temp gauge would fluctuate a little between R and the U once warmed up. That didn't take very long. I then removed the grill covering after about 45 minutes and the gauge would drop just into the cold and then back almost to the U. Guess I will have to wait until next summer to see if the thermostat stays installed.

I have been using my Cub with the thermostat for almost a year. Worked great last winter pushing snow. I wasn't sure how well it would work cutting grass at temps close to 100. Before the thermostat the temp gauge would be steady at the U in Run on a 95 degree day. Now on a mid 90 degree day it reads between the R and U in the gauge. My thought is that the thermostat restriction allows the radiator to cool the coolant better. I remember hearing that an auto will overheat quicker without a thermostat than with one.
https://askinglot.com/what-happens-if-y ... t-in-a-car

Hi,
I think you might have installed the sender for the temperature gauge in a place where it it not giving you an accurate reading.
You didn't say quite where the sender is, or post a picture.

On the tractors I have seen with a temp gauge, the sender is at the top of the engine, on the head, or water elbow to the top of the radiator. That is where the water is the hottest, as it goes into the radiator.
Water is cooled going down through the radiator, then it goes into the engine through the lower water elbow.
The water is the coolest at the bottom of it's travel.

If the sender is low on the engine, the gauge is probably going to read cool, even when the upper area of the engine is hotter.

tnestell wrote:I remember hearing that an auto will overheat quicker without a thermostat than with one.
https://askinglot.com/what-happens-if-y ... t-in-a-car

That's because a car has a water pump and without a thermo to control flow the coolant circulates too fast for it too cool sufficiently in the radiator.

Unless your temp sending unit is mounted in the head or very near the top you're not getting an accurate temp reading. I'm pretty sure if a thermo in a Cub was a good idea it would have come from the factory with one and it would be recommended in the manuals. It isn't.