I'm guessing Thermostat

wolfman

Well-known Member
CIH 585 by the time you get to the field the temp gauge is on the hot side. Remove radiator cap, no steam or excess pressure. Run the tractor a while and the gauge comes back to a more normal reading. All this with light work trim cutter bar half throttle. I'm guessing thermostat sticking. Replace it or ???
 

A friend has a 685 that has always been the same way. It runs hot on the road, get into the field and go to work and the temp comes down.
 
Well, if it runs up and then back down something is opening and allowing flow. The primary purpose of a thermostat is to cause cooling in an engine. One of my pickups does that but didn't start until I let it set in the barn a year. Same thing, goes way up there to the point figure is going to boil over, then opens and runs correct until next time. I'm going to rebuild it, so no big deal. You don't have to replace your thermostat, but it might not be a bad idea if its uncharacteristic of how its performed in the past. Would I change it? It's your tractor, your decision.

Mark
 
Are these the systems that need distilled water and a correct 50/50 mix ? Thermostats are cheep. Also are there air pockets somewhere? Lastly could it be if you have not maintained your cooling system correctly the cylinder walls have cavitated and you're sleeves now have tiny holes. Engine pressurizes the cooling system, thus your air pockets and crappy cooling.
 
You can change it,but I have my doubts that it's the problem if it's cooling back down. Is the fan belt good and tight? I've had two of them lately that the tubes in the radiator became plugged with lime scale,rust and what not. I had one recored,replaced the other with a new radiator,but those just kept getting hotter unless I stuck a hose in front of the radiator and ran cold water through the fins for a few minutes.

I was talking to a cousin last night who said his 6410 Deere was overheating. The block was hot,but the radiator wasn't. Ended up being the plastic impellers in the water pump had gone to pot.
 
I'm wondering if possibly the gauge is wrong. Is it electric or mechanical?

Not likely a mechanical gauge could do that, but electrics can do strange things.

If it were really hot, as over to the danger zone, and the cap was opened, there should be a lot of steam and boiling.
 
While I doubt if it's your trouble, I had a 6400 that would read high, then normal, spike to high and back to normal. Temp was ok on everything except the gauge. Turned out to be a ground connection on the engine from the dash was loose. Drove me crazy for some time........
 
It could be the thermostat is slow to open at first,and sticks closed until the head gets a little hot,and then opens and stays normal the rest of the day.OR-as donjr says-it's a gauge problem.If it is showing hot the first time you run it,is the top of the radiator hot? But not boiling out? Then I would suspect the gauge and/or its wiring.You can get an infra red thermometer and shoot the head near the temperature sender and the thermostat and get a pretty close reading to what the gauge should show.Then you would know.You can also use the infra red for checking bearings,too.Mark
 
Might want to get one of those laser thermometers to check what actual temps are at different times.
 

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