temp gauge

loose nut behind the steering wheel

Move towards cooler side, how? It just marginally goes cooler or does it peg to the cooler side? Does it immediately move or take a couple of seconds.

If it just marginally and slowly moves (ie within a couple of second), it is just a function of more air moving along the engine/radiator and thus cooling the engine more. It may dip a little, but the car should stay within certain temperature margins to run correctly. If it dips a lot and stays there, it could be that your thermostat is stuck open and the engine is just running too cold. Does your car take longer to heat up lately? If so, that is also due to a stuck open thermostat. This is not a catastrophic failure, but I'd replace it because your engine will not run correctly. A stuck closed thermostat, on the other hand, will cause overheating.

If your temperature gauge just dips immediately after you start driving, your temperature sensing mechanism might be faulty - most likely an electrical problem. Immediate dips (ie. zero time) are near impossible to be caused by temperature.

Hope this is useful. Remco

Mine was doing the same thing. I would check the wire going to the sensor in the thermostat housing. Mine was loose so I just gave it a twist and it fixed the problem. It is riveted to the sensor or something. You'd understand better by looking at it.

I had the same problem. I would check the wire that goes to the sensor in the thermostat housing. Mine was loose so I gave it a twist and everything works now. It is riveted to the end of the sensor. You'll understand when you look at it.

Look at the wire going to the temp sensor. Mine was loose where it connects to the sensor on the thermostat housing. I just gave it a twist until it was tight again. It is riveted to the end of the sensor. You'll understand when you look at it.