temp gauge d2 v8

hi some advice please,temp gauge on d2 v8,rises to normal then somtimes will drop to nearly cold then minutes later will rise again then will drop again randomly no coolant loss all seems ok.is it the gauge/sender playing up or air somewhere,
thanks for any help

sounds like low coolant or poor sensor ,level in expansion tank is not necessarily the same as engine

air in the system IMO as first call... bad contact in plug/wiring issue or bad sensor

The connector on the Thor engine isn't the most brilliant design, and is in line for road spray & salt coming through the radiator. I'd undo it and check the pins and the wires to the pins to see of you have corrosion on the pins or between the pins.

The sender itself is pretty reliable, just the connection is a bit weak.

Peter

thanks for all info ill look at these possibles