McCormick CT28 overheating - thermostat?

[mtaves]

Hi everyone,

This may be a silly question but will put it out there regardless: tractor was overheating so shut it down. Has been running hot and just figured it was all the dandelion fluff plugging it up. It is definitely more serious than that...

Looked under the hood and cannot see any obvious flange on either radiator hose where a thermostat should be. Under troubleshooting section in the owner's manual it only says to make sure you have coolant and that the fan belt is tight enough.

Is it possible there is no thermostat? If not, any ideas what else could be causing the overheating?

Martin

 

[mtaves]

Answered my question - yes there is a thermostat. Unfortunately, replacing it did not resolve the overheating problem. This leaves me with two other options, I think: either there is a blockage in the rad somehow, or air is not getting through the rad. With all the dandelion fluff blowing about this spring, I have been blasting off the intake side a fair bit to keep it clear but tried to be careful about bending over the thin metal fins with the high pressure air stream. The tractor has never run quite right with respect to temperature control. I got a great deal price-wise, but took a calculated risk as it had virtually no rad fluid at the used dealer. The oil has always been the proper colour, and fluid level has never dropped since I topped it up - so I know it is not leaking into the engine.

 

[buzzard3]

Hi everyone,

This may be a silly question but will put it out there regardless: tractor was overheating so shut it down. Has been running hot and just figured it was all the dandelion fluff plugging it up. It is definitely more serious than that...

Looked under the hood and cannot see any obvious flange on either radiator hose where a thermostat should be. Under troubleshooting section in the owner's manual it only says to make sure you have coolant and that the fan belt is tight enough.

Is it possible there is no thermostat? If not, any ideas what else could be causing the overheating?

Martin

Hey Martin,
I have the same overheating problem with my 125. I put in a new thermostat and temperature sending unit. Still is overheating on the gauge. What did you find out with your tractor?

Thanks Martin
David

 

[mtaves]

Hi David,

No good news I'm afraid. A new thermostat didn't solve the problem. I didn't think about the sending unit, but know it is working because I hear water start to boil over at about the same time as the gauge shows that I am in trouble. Leaving the tractor off for 5 minutes then turning on again results in a slight temperature decrease on the gauge before things rise again, so I know the radiator is not totally blocked. Maybe partial blockage? Don't know. Maybe I did more damage than I thought when blasting dandelion fluff off the radiator fins, even though most of them are hidden behind the transmission cooler. Partial blockage and bent-over fins are the only 2 ideas I haven't tested yet.

I wish you better luck than what I am having, and hopefully a lower repair bill (assuming I need to buy a new rad...).

 

[buzzard3]

Hi David,

No good news I'm afraid. A new thermostat didn't solve the problem. I didn't think about the sending unit, but know it is working because I hear water start to boil over at about the same time as the gauge shows that I am in trouble. Leaving the tractor off for 5 minutes then turning on again results in a slight temperature decrease on the gauge before things rise again, so I know the radiator is not totally blocked. Maybe partial blockage? Don't know. Maybe I did more damage than I thought when blasting dandelion fluff off the radiator fins, even though most of them are hidden behind the transmission cooler. Partial blockage and bent-over fins are the only 2 ideas I haven't tested yet.

I wish you better luck than what I am having, and hopefully a lower repair bill (assuming I need to buy a new rad...).

Martin,
I believe I have no fluid circulating. The radiator is cold. The top hose is warm and the bottom hotter. I can open rad cap without boiling out. I can tip my finger in the fluid without burning so I am figuring 150 degree

I do t see the water coming in from the top hose, but when I squeeze hose I get some movement.

Am figuring the new thermostat is bad or the water pump is shot.

Dave

 

[mtaves]

Dave,

You seem to be much better at troubleshooting than I am. Thanks for the tips!

Next time I start it up I will check the temperature in the rad. Pretty sure that both my hoses will be warm, since I get water boiling over into the overflow tank, but that does not mean I am getting circulation in the rad itself.

I don't know how long the tractor was being operated without coolant before I brought it home. Running a water pump without any coolant in it would definitely shorten its expected lifespan.

Martin

 

[mtaves]

Finally solve the problem - in a place that I should have checked first. I committed to spending an afternoon working on the problem, pulled the air breather off and pulled the oil cooler mounting bolts off so I could push it off to the side. The radiator fins were caked pretty much solid behind the cooler. After two hours spent with a combination of blowing debris clean and hosing it with low pressure water, it now runs fine. Spent 45 minutes mowing through grass about 18" long and it never even reached the midpoint on the gauge. $0 spent, problem solved, and a thorough rad cleaning each spring will be added to my spring maintenance checklist.

 

[mguitas]

I know it was three weeks ago, but i'm glad you found the problem.

 

[mtaves]

Thanks! and I am glad it was fixed so cheaply.
Hopefully this thread helps someone else down the road with working through all the inexpensive possibilities before they go and spend their hard earned cash.