I was hoping someone could help me, I have a 1 ton diesel dodge the thermostat needle started going back and forth rel slow, it goes up to 210 then stays a minute or so and then goes back to 165 or so back and forth very slow though. put in a new therm and new radiator, nothing new, it doesn't leak any anti freeze either. had the radiater pressure tested, nothing. It has never over heated either.



Any suggestions? Thanks ciera56

 

I'm guessin that's where the fan kicks on and off.

 

Sounds like temp sensor/ 40* is alot to cool down to when fan kicks in.

 

I would assume the sending unit for the gauge is bad not sure of it's location ,but it's something to look at.[sm=confused06.gif]

 

I want to thank you for the responses. I'm a female so its hard to know what to do. I'll have all of the above checked.