TC40 Running Cool

dknarnd · Sep 30, 2007

Was pulling some logs out for firewood Saturday and noticed that my temp wasn't going up. Felt the hoses and they only felt warm, not hot, so I was thinking probably the thermostat; pulled the wire off the sensor and the needle dropped completely.

No internet where my tractor is located so now that I'm back home I searched and found a post from 2006 where jinman talkes about the thermostat and how to check the sensor. What sucks is my tractor is 4 hours away so I can't test. It's still under warranty so guess I'll call the dealer tomorrow and see if they will send me a thermostat and gasket and let me replace it. Can't see them working on it either because it is 1 hour away from them, cheaper for me to buy the thermostat and replace it myself, taking the chance the sensor is alright.

DocHeb · Sep 30, 2007

The "thermostat" part of the earlier TC40s wasn't defective, just the "dingle-ball" that was supposed to let air through, but not fluid in the opposite direction. A fix that has been suggested in the past is to take out the thermostat, cut off the "dingle-ball", pop-rivet the hole shut, then drill a small 1/16" hole to let air by.

dynasim · Sep 30, 2007

I just cut the dingle ball off.

No more problems.

Chris

jinman · Oct 1, 2007

Don't forget the block drain hose from the engine block to the radiator. Most of us have added a cutoff in this line. If your tractor is like this, the little hose can supply enough fluid to keep the tractor running cool. (see attachment)

The other thing is the temperature gages are not very good. Several of us have had to replace the gage. To check it's operation, Turn the ignition to ON. Remove the lead going to the temperature probe and ground it momentarily. The gage should go all the way to maximum hot while the wire is shorted to ground. If not, the gage is defective.

So, you are faced with three possible problems:
1. thermostat
2. bypass hose
3. temperature gage

It could be one or a combination of all three. Good luck!

dknarnd · Oct 1, 2007

I didn't notice this "block drain hose" you mention but I will have to take a closer look next time. What does this hose do?

Anyway I talked to my dealer today and they are expecting parts this week to do an ignition change on somebodys tractor that is near me so they are going to schedule them both the same day; good deal since I'm 100 miles away. I'm under warranty so they will handle it.

jinman · Oct 2, 2007

dknarnd said:
I didn't notice this "block drain hose" you mention but I will have to take a closer look next time. What does this hose do?

Anyway I talked to my dealer today and they are expecting parts this week to do an ignition change on somebodys tractor that is near me so they are going to schedule them both the same day; good deal since I'm 100 miles away. I'm under warranty so they will handle it.

Instead of having two valves to drain the engine coolant, NH attached a hose from the engine block to the radiator so you can easily drain both by draining the radiator. Unfortunately, the hose from the block allows coolant to bypass the thermostat. In very cold climates it is enough to keep the engine from ever getting warm enough to be in the operating range. By putting a valve in the hose, you stop that bypass and return the system operation to normal.

dknarnd · Oct 3, 2007

Well it was just the thermostat, service guy showed up today and had it going in less than an hour.

Soundguy · Oct 4, 2007

Thanks for posting back. many times we don't get to ehar the rest of the story.

Also interesting that CNH has not modified this design any to prevent that ball from cocking over and holding the thermo open.

Soundguy

jinman · Oct 4, 2007

dknarnd said:
Well it was just the thermostat, service guy showed up today and had it going in less than an hour.

That's cool!...no...uh..warm! That's it! Warm is cool!

jimmysisson · Oct 4, 2007

Actually I like that bypass hose, as it is a lot simpler to drain coolant. Like others, I installed a shutoff in the hose. It makes a small difference in the winter temps. If I forget to open it in the spring, usually can't tell by the guage. My 2120 runs low-medium on the guage, feels pretty warm on the hoses.
Jim