TC33d overheat problem

[Eric F.]

I haven't been on in a few days...
I have an IR thermometer, will compare readings. There are no other signs of overheating with this machine, when loaded it runs 3mm above the white (normal) bar, 3mm from the red. Clearly by guage standards it is over ideal temp. Is the sending unit or guage off, could likely be. The t-stat cap will also hold pressure, not venting out overfilled water as it heats up. I do believe it is time for a new cap.

So the IR guage to the upper radiator tank area should be 180-190? In the automotive world t-stats are usually 195, I am unfamiliar with diesel t-stat design, but a 195 would be about 10 degrees cooler when measured at the upper tank, eh.

Thanks,
Eric

 

[Eric F.]

I heated it up today, guage in the upper green as it has been.

Took IR readings:
Thermostat housing on the eng: 215 degrees
Upper radiator tank near the hose: 204 degrees

Any ideas, I trust this represents a mild overheat condition.

 

[jinman]

I heated it up today, guage in the upper green as it has been.

Took IR readings:
Thermostat housing on the eng: 215 degrees
Upper radiator tank near the hose: 204 degrees

Any ideas, I trust this represents a mild overheat condition.

I checked the Repair Manual for my TC45D and came up with the following stats for the thermostat:

Starts to open - 176-183 F
Fully open at - 203 F
Radiator Cap - 13 psi

I think your thermostat is similar. My guess is it is a 180 degree F thermostat and I'd check to make sure the wrong thermostat was not installed. Your tractor is running on the high side and mine has only done that when the radiator is clogged with grass "cotton" while mowing. Yours does seem to be running a little high, but nothing to be alarmed about if it doesn't go higher.

 

[JC-jetro]

On my 1700 The resistance of temp sending unit is right at 180 ohms when my temp needle is right in the middle when the tractor is at full operational temp. Jim,I wondered if your manual gives info on that for cross check.

JC,

 

[jinman]

On my 1700 The resistance of temp sending unit is right at 180 ohms when my temp needle is right in the middle when the tractor is at full operational temp. Jim,I wondered if your manual gives info on that for cross check.

JC,

JC, my manual does have ohm readings for the sending unit at various temperatures:

95 F = 670 ohms + or- 80 ohms
176 F = 118 ohms + or - 6 ohms
221 F = 54.5 ohms + or - 2.7 ohms
239 F = 42 ohms + or - 2.5 ohms

That being said, since the temperature of Eric's tractor is indicating the same as his IR thermostat says, I'd say these readings on the sending unit are probably just fine.

Also, I had a temperature gage that was reading exactly the resistance described in testing in the manual, but it was only reading 1/2 scale. The new meter read the same, but it worked perfectly. I'm not sure how much I trust these numbers. My dealer's service manager suggested I disconnect the lead from the sending unit a see that the gage read zero. Then, ground the lead going to the gage with the key on, and the gage should read maximum. That was the test that told me I had a bad temperature gage because grounding the gage only gave me 1/2 scale deflection.

Since Eric's IR thermometer agrees with his gage, I think his temperature system is working fine. But, as you say, it doesn't hurt to check the sending unit with the numbers above. That does give you another data set to work with.

 

[JC-jetro]

JC, my manual does have ohm readings for the sending unit at various temperatures:

95 F = 670 ohms + or- 80 ohms
176 F = 118 ohms + or - 6 ohms
221 F = 54.5 ohms + or - 2.7 ohms
239 F = 42 ohms + or - 2.5 ohms

That being said, since the temperature of Eric's tractor is indicating the same as his IR thermostat says, I'd say these readings on the sending unit are probably just fine.


Since Eric's IR thermometer agrees with his gage, I think his temperature system is working fine. But, as you say, it doesn't hurt to check the sending unit with the numbers above. That does give you another data set to work with.

I agree Jim,

unfortunately at least on my tractor gage I did not see a pot for calibration of the gauge. If you have that on your newer tractor you might be able to get the tractor to operating temp, corroborating the the temp sender resistance and adjust the pod where the needle would be right in the middle. I suppose zeroing the needle is an attempt to see if the gage is calibrated right. I see that we have a slight high temp in the safe region. I'd be interested to take the t-stat out and slowly bring it to a boil in a pot to see if it indeed fully opens. if that's so then got to be flow (pump or obstruction) or heat transfer (radiator and fins maintenance).

JC,


JC,

 

[jinman]

I agree Jim,

unfortunately at least on my tractor gage I did not see a pot for calibration of the gauge. If you have that on your newer tractor you might be able to get the tractor to operating temp, corroborating the the temp sender resistance and adjust the pod where the needle would be right in the middle. ,

No adjustment JC, just a very expensive gage to replace if it fails, $50. Here are some photos of the gage and the test with the details on the manual in the background. I suspect Eric's gage is similar, but I can't be sure on his Class II TC33D.

Like you, it seems I have a picture of almost everything I've ever done to my tractor.

 

[JC-jetro]

Like you, it seems I have a picture of almost everything I've ever done to my tractor.

WOW, so I'm not the only "different... saying it mildly!!" person here. I have been contemplating at times to see a shrink to see if there is anything wrong with me, lol

JC,

 

[BigE_]

Reviving a very old thread, and somewhat hi-jacking since I've got similar problems on my TC33D, except that it will now overheat even when idling. When I first got it, I could barely get the temperature gauge to go into the green unless I was really pushing it. Now it goes into the green after 5 minutes of use, and will go into the red after 15 minutes of use (and much of that is at 2800 RPM in 3rd going down the road).

If I spray water on the radiator while running, it cools down quickly.

The radiator was a little dirty, so I removed the screen and cleaned it out thoroughly. No plugged fins, and I can see through it just fine in most places. The hydraulic fluid radiator was a little dirtier. I took that off and thoroughly cleaned it, and also straightened some of the fins that were bent. Finally, I made sure that the fan belt was tight.

It still starts getting hot quickly. Reading back through, I noticed a section about air leaks. Could this be my problem?

I shot a video of the radiator fluid movement once the tractor got warm. There is definitely a lot of bubbles coming up through. Could someone please review this video and tell me if it is normal, or if I have a head gasket change out in my future?

The good news is that I'm not getting white exhaust, and the oil is not getting water in it.

[youtube_browser]jbhfwGbndQc[/youtube_browser]
First I have the tractor at about 2500 RPM, then I lower it down to an idle, and finally raise it back up to about 2300RPM

 

[k0ua]

Well, I am not a mechanic and I don't play one on TV either, but my thought is where else can all those gas bubbles be coming from? Well the exhaust that's where. The exhaust gasses are very hot, and raise the temp of the fluid also.. So I am thinking, yes a head gasket is in your future, and soon

James K0UA