802a Coolant Fault Light

Hi everyone, thank you for the replies and help. I am going to borrow an infrared thermometer tomorrow to do some further testing.

Guy, thanks for the switch info, I did not come across that yet.

FSK, I have what I believe to be an OEM temperature gauge. It did show 180 degrees earlier when I was doing some testing but even at that reading the fault light was on. I will have to do some testing with a multi meter.

Ray, the fault light comes on before the gauge gets to 180 degrees. The upper radiator hose is warm and the lower hose is much cooler. The engine compartment does not seem to be excessively hot.

Well if the top hose is hot, and the lower hose significantly cooler... I would stay the T stat is at least functioning (possibly not at its peak, but lets put that aside for right now).

If you are getting the fault light at varying temperature levels, thats due to this puppy: https://www.ebay.com/itm/124183942354

It sounds like the thermostatic switch is in the process of failing. I would replace that. I would flip down the gauge panel, and see if there are any stickers on the body of the gauge, with a part number on them. Here are the items which could have been installed at the factory:



Does yours match any of those? Those items would have been matched to the factory sender (which does fail, albeit not often). If the gauge has an alternate number on it, it might not match the sender in the machine, which would cause bad readings on the gauge.

If this were me? I would pull the temp switch like mentioned above, and completely drain the cooling system and flush with distilled water a couple of times. At the same time, I would put in a new thermostat (its real handy to refill the cooling system the majority of the way, through the thermostat hole into the water jacket on the block to remove the chance of air pockets being trapped) and then reinstall the top hose, and refill through the radiator neck.

Only then, would I start to reassess whats going on. You at least then know the thermostat should be working properly, and take that out of the equation. With a new T stat and a new temp switch, you are down to determining which part of the temp gauge/sender system is at fault for the gauge readings.

Light in the Dark said:

If this were me? I would pull the temp switch like mentioned above, and completely drain the cooling system and flush with distilled water a couple of times. At the same time, I would put in a new thermostat (its real handy to refill the cooling system the majority of the way, through the thermostat hole into the water jacket on the block to remove the chance of air pockets being trapped) and then reinstall the top hose, and refill through the radiator neck.

Only then, would I start to reassess whats going on. You at least then know the thermostat should be working properly, and take that out of the equation. With a new T stat and a new temp switch, you are down to determining which part of the temp gauge/sender system is at fault for the gauge readings.

Click to expand...

I took a look and there is the remains of a sticker on the gauge but I can't see any writing on it.

I did fire the set back up this morning and it has run now for 9 hours and has not set the coolant high temp fault light. The gauge is showing around 200-220 like yesterday. When I get power back I will do the above. I want to do an oil change so changing out the coolant/thermostat can be done then. I will also order one of those thermostatic switches as well.

Thank you everyone for your help!

So a quick update, I ran the generator all day yesterday keeping an eye on it. The radiator burped out about 12 oz of coolant through the tube at the radiator cap. My guess is there was an air bubble in the system. It is showing about 20 degrees cooler on the gauge and I have not had the fault light come back on.