Thermostat for a John Deere M

My John Deere M is running warmer than it should. It should be running at about 180 degrees, but it is running at over 200. It"s not boiling over. Does this model have a thermostat, and if it does where is it located on the cooling system?

All Ms appear to be running hot. My MT runs 210 -220 under load according to the gauge. They don't have thermostats or a water pump. If steam isn't coming out of the radiator, then it is ok.

Sounds like your running at about normal temp. The temp gauge on these tractors are located near the hottest part of the head.

You want it to be running at 210 - 220 at load. I get more concerned when I can't get mine warm in the winter than when it gets hot in the summer. The system for cooling is a thermosyphon system. Based on the right level of coolant and transfer of hot to cold the fluid will move on its own in the system. No t-stats in the system. Make sure you get a manual and put in the right amount of coolant. Too much coolant is as bad in this system as not enough. It needs room to move so full to the cap is too much coolant.

There is no thermostat for either the M or the MT tractor; the <a href="http://books.google.com/books?id=ZgzC12uABc4C&pg=PA76&lpg=PA76&dq=john+deere+thermosyphon+principle&source=bl&ots=4ftjMWlNMx&sig=yBqcNywydJo3Zwt-3-x3xF5SGBo&hl=en&sa=X&ei=Uu5mUPWGO5Di9gSE4IHYCw&ved=0CFEQ6AEwBg#v=onepage&q=john%20deere%20thermosyphon%20principle&f=false">thermo-syphon principle</a> is used for the cooling system.

Installed a new radiator on "Sam" one of our 51MTs and idle temperature is 180^o.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/SAM/Temperature%20Gauge/?action=view�t=IMG_3043.jpg" target="_blank"> </a>

The temperature rises to 210^o under a load either raking or mowing even with a new radiator.

You can use a "kitchen" thermometer to check the accuracy of the temperature gauge.

There has been some discussion in the past that the location of the sending unit also has an effect on temperature.

If the temperature gauge sending unit is located on top near the heat shield, then the temperature might read higher.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/SAM/Temperature%20Gauge/?action=view�t=IMG_3131.jpg" target="_blank"></a>

If the temperature gauge sending unit is located on bottom of the block near the oil line, then the temperature might read lower.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/SAM/Temperature%20Gauge/?action=view�t=IMG_3134.jpg" target="_blank"></a>

Cleaning or flushing the radiator might also help.

The operator's manual recommends about 3<font size=1>¹/₂</font> gallons of water in the radiator.

There has been some discussion in the past that over-filling the radiator might cause the thermo-syphon cooling system to operate incorrectly.

Hope this helps.