Hi chaps.
A while ago I replaced the thermostat in our 2005 RRSS as the temperature gauge was showing erratic readings. I also put in a new temp sensor.
Well, the same is happening again..
Cold start engine temp goes up to middle as it should but then it drops to 1/4 and the viscous fan is running - this is within 15 min of driving so the fan should not be on. Eventually the gauge shows just under 1/2.
If I stop the engine for a few minutes and restart it runs normally - almost like its reset itself.
Coolant level is ok.
Thoughts? Duff sensor even though its new?

If anyone can shed any light on this..
I replaced the cts last week and it's been OK. This morning though it returned back to the temp dropping down to 1/4 after being at 1/2 with the engine running for 10 - 15 minutes. The fan is coming on again. The engine cannot be hot enough at this point.
What is going on? It can't be 3 failed temp sensors and the thermostat is new.
I bled the cooling system when I replaced the cts by loosening the small cross headed screw to the right of the cts.
Baffled..