Temperature issues

[Baz]

I know everyone has had temperature/heating issues with Spiders. I have done all the good stuff with the cooling circuit and still my guage fluctuates...sometimes goes to red, then drops back...sometimes does not drop back. I have replaced fan switch with a 'on at 92 off at 87' unit, so I know we are not overheating. I have checked the earth to the guage and all seems fine. The sender switch on top of the head is not much older than 2 years. Has anybody else had this problem and solved it ?? if so....fix ?? It may well be the guage itself..but this is such a great forum I thought there may be a home remedy.
Thanks
Baz

[So Cal Mark]

the sending unit can cause erratic readings, but you need to find out whether the engine is really hot or not. Can you measure the temperature with an infrared gun or thermometer?

[mbouse]

please tell me you've already mastered the burping of the cooling system. if not, send me an email to mbouse@chartermi.net and I will forward you a copy of the well documented procedure.

[Baz]

Yes, I have done the well documented procedure, done all the bleeding and burping, also the temp is not exceeding 92 as the fan comes on as it should...its just either the sender unit or the gauge is crook. I have owned a few fiats (130,125,125s and 125T) but never had this problem.
Baz