Kubota GR2110 Overheating?

[smketr]

Good afternoon. I am new to this site and would very much appreciate help/advice with the following issue: I recently inherited a 3 cylinder diesel Kubota GR2110-54 lawn and garden tractor with 502 hrs on the hour meter. The tractor was very well maintained by the previous owner performing all of the hourly maintenance required by Kubota. I used the lawn tractor for about 20 hrs to date. Yesterday, after mowing for about an hour, I noticed that the coolant temperature light was very “dimly” lit. I had no issues with lawn tractor while mowing. Because of the bright sunshine, it was very difficult to even see that the light was “dimly” lit. The engine coolant was full, fan belt tight, radiator free of grass clippings/debris, air filter new, no leaks or steam. I shut the engine off and let it cool down over night. The next morning, I started the engine and let it run. When I turned the key to the “accessory” position, the oil pressure light and the electrical charge light came on and were “bright white” in color. The coolant temperature light was off. After about a minute of running, the temperature light came on very slowly and stayed “amber” in color (like a light on dimmer switch at its lowest setting). See attached photos:

The first photo is the coolant temperature light after the engine was running for about a minute. The light never got brighter the longer the engine ran
The second photo is the coolant temperature light (left) not on and the oil pressure light (right) “bright white“ when the ignition is in the “accessory” position.

I Is the engine actually overheating? Any thoughts as to why the coolant temperature light is coming on after only a minute?
I am going to purchase an infrared thermometer gun to get an idea of the engine temperature. I would appreciate any advice on the cause and how to fix.
Thank you.

 

[lmichael]

Had something similar happen. Turned out I had bumped the ign switch. It was in between "off and run". My tractor does not have a stop solenoid. The original went bad, so I simply rigged up a knob to pull out on the dash to stop the engine. Simple, works and nothing to go wrong. Try turning it off and re-starting it

 

[GreensvilleJay]

curious, it may just be a 'thermo switch', that only closes above a certain temperature (say 160*F ), so the lamp should be either off or bright. Dim, as shown suggests a small amount of current is getting through.
simple test, remove wire at sensor and touch to ground. The lamp should glow bright. If so, then the your sensor is defective. If dim, swap bulb with the other. It 'might' be the wrong bulb.
If all the other bulbs and gauges work fine, then it's not a 'ground' issue. Doubt it's a 'power feed' either, as everything else is OK ?
would need a real part number and/or wiring diagram but my 'gut' says bad sensor.

 

[lmichael]

My incident happened right after I washed the engine and tractor (clean engine = happy engine). Maybe soap residue was carrying a trickle current IDK

 

[smketr]

Thank you very much for everyone’s reply.
I have not washed the engine since the previous owner kept the tractor pretty clean. I too like a clean engine so I will be cautious when cleaning in the fall. I believe my ignition switch is working properly. I have started/restarted the engine numerous times and same results. I did swap the bulbs and had the same results, dim light after about a minute. All of the other bulbs and gages are working okay. I also cleaned the thermo sensor contact but still a dim light. The wire connector to the thermo sensor looks a little corroded so I will replace. I will try grounding the thermo sensor wire and see what happens.
Kubota’s sensor, thermo switch, for my engine is #16851-83043 but Kubota lists it as unavailable. I will have to search the web to see if one may be available. Thank you again for everyone’s advice and suggestions. Have a great day

 

[GreensvilleJay]

Part Details | Coleman Equipment

only $38, but also show same part as $70 !
seems to fit several machines...

 

[lmichael]

In the mean time perhaps get an actual gauge and check it. Or simply install a gauge and be done with it. My goal is to have a temp gauge, oil pressure gauge and a tach eventually

 

[smketr]

I really like the idea of using gages instead of depending on the lights. For now I will give Coleman Equipment a call and see which thermo switch is compatible for my tractor. Thank you for all of your suggestions.

 

[ve9aa]

curious, it may just be a 'thermo switch', that only closes above a certain temperature (say 160*F ), so the lamp should be either off or bright.

Dim, as shown suggests a small amount of current is getting through.

simple test, remove wire at sensor and touch to ground. The lamp should glow bright. If so, then the your sensor is defective. If dim, swap bulb with the other. It 'might' be the wrong bulb.

If all the other bulbs and gauges work fine, then it's not a 'ground' issue. Doubt it's a 'power feed' either, as everything else is OK ?
would need a real part number and/or wiring diagram but my 'gut' says bad sensor.

This....right here. All of it.

 

[smketr]

curious, it may just be a 'thermo switch', that only closes above a certain temperature (say 160*F ), so the lamp should be either off or bright. Dim, as shown suggests a small amount of current is getting through.
simple test, remove wire at sensor and touch to ground. The lamp should glow bright. If so, then the your sensor is defective. If dim, swap bulb with the other. It 'might' be the wrong bulb.
If all the other bulbs and gauges work fine, then it's not a 'ground' issue. Doubt it's a 'power feed' either, as everything else is OK ?
would need a real part number and/or wiring diagram but my 'gut' says bad sensor.

‘Good afternoon GreensvilleJay. I grounded the wire from the thermo sensor like you indicated in your post and the lamp glowed bright white, indicating that the sensor is defective. Your ‘gut feeling‘ was correct! Thank you. One more question if you don’t mind. Do you think this “bad sensor” will still alert me if there is an overheating problem if I use the mower? I have a new sensor on order but it’s going to be a few days before I receive it. That being said, I don’t want to risk an overheated engine melt down just to cut the grass. I would appreciate your input. Thank you.

 

[smketr]

This....right here. All of it.

I grounded the thermo sensor wire and the bulb glowed bright white. Ordered a new thermo sensor. Thank you for your input.

 

[GreensvilleJay]

One way to test would be to remove sensor from engine, ground the case, turn key on, it should glow dim,then heat it up LIGHTLY with a match or BBQ starter.
probably have to jam a cork into the hole, temporarily......

 

[smketr]

One way to test would be to remove sensor from engine, ground the case, turn key on, it should glow dim,then heat it up LIGHTLY with a match or BBQ starter.
probably have to jam a cork into the hole, temporarily......

Thanks. I will give that a try. Have a great weekend.

 

[smketr]

‘Good afternoon GreensvilleJay. I grounded the wire from the thermo sensor like you indicated in your post and the lamp glowed bright white, indicating that the sensor is defective. Your ‘gut feeling‘ was correct! Thank you. One more question if you don’t mind. Do you think this “bad sensor” will still alert me if there is an overheating problem if I use the mower? I have a new sensor on order but it’s going to be a few days before I receive it. That being said, I don’t want to risk an overheated engine melt down just to cut the grass. I would appreciate your input. Thank you.

 

[smketr]

Good Afternoon. Finally received the new thermo sensor and installed this morning. GreensvilleJay and ve9aa were spot on with their diagnosis of the “dim” temperature light problem. New sensor solved the problem. Thank you!
Also, thank you GreensvilleJay for suggesting Coleman Equipment for the sensor. They had the new sensor in stock for only $38.00. Appreciate all the advice from the forum members.