753G temp gage misbehaving

[Creek Jenkins]

I have a 2002 753G with 950 hours on it. Occasionally the temp gage swings wildly from green to yellow, sometimes even into the red, shutting the engine down. I was thinking stuck thermostat, but checking the engine temp with a FLIR, it is not hot. Even at idle and not operating anything the temp gage will swing back and forth. I can hear it clicking sort of like a clock. Then it will settle down and I can operate it fine for the rest of the day. Only happens occasionally, 4 or 5 times a year, but is getting more common lately. Rad and oil cooler are clean and fan is moving very good air flow. I changed antifreeze about 4 years ago, I put on roughly 60 or 70 hours per year (I bought it in 2010 with 430 hours on it), just use it for cleaning the barn, occasionally moving some dirt, and snowblowing in the winter. Could it be the sending unit or something in the BICS system? Anyone seen this problem before? cheers, Creek

 

[foton]

I do not know about your machine but I will say that usually it is the sending unit that fails regardless of it's application. Unless you have had problems with your harness already.