# New to me '66 JD 4020 DSL engine (coolant) temp sensor location?



## Ace Cattledog (8 mo ago)

The temp gauge does not move. I am reluctant to operate for very long without a good idea of the engine temperature. I imagine the gauge could be bad, the sensor or the connecting line. Questions:
Where is the sensor located?
Test procedure?
How to test the temp gauge?
Also, any tips on testing the fuel gauge and sender?
Thanks for your patience and help. Ace


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## BigT (Sep 15, 2014)

Howdy Ace, welcome to the forum.

The factory temperature gauge for a 4020 is the old style capillary/manual type with sensor attached to the gauge by a tube. No electric involved. Check it out.









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The fuel gauge sending unit is a float on an arm in the tank that varies resistance (ohms) with float level (rheostat at pivot point) . You can test the gauge by touching the float unit wire to ground. Gauge should go full scale.


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## mark pritzl (Apr 20, 2019)

I own a 67 John Deere 2020 that I bought used and the temp gauge didn’t work either. The local dealer said it was still available so I ordered one and it works perfect. It is the capillary type and it connects to the top rear of the cylinder head. There are no wires involved so it continues to read after shutting the tractor off. However you could easily install an aftermarket electric gauge but you would have to wire it to the ign switch for 12 volts when the key is on. The dealer oem gauge is quite expensive ($180) while an aftermarket gauge is under $30.


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## Tx Jim (Jul 28, 2020)

Welcome to the TF
Temp gauge capillary tube bulb is located on top of rear of engine cylinder head


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