You don't need to replace the one in the radiator. You might remove the one from the top of the engine and clean off any calcium buildup on it, which could impact how fast it changes temperature. And any sensor can fail or be out of range, it iz not a purrfect wurld.

 

Savanah -

I hear what you are saying about an imperfect sensor!

I have the new sensor for the top of the engine so I will just replace it since they are not expensive. I am then going to flush the rad with water, replace the t-stat again and then I will take note the temps. on the radiator both top and bottom.

If my cooling fan keeps coming on after that then I will be a little lost!!

I already have a new water pump, new fan clutch, new serpentine belt amongest other new parts! I was quoted 14 hours book time to do the head gasket which may be done in the not so far off future.