This just started happening today. I have no idea what is going on but my car will sit over night and when I go out in the morning to start it to go to work the coolant temp gauge will say it is already at normal operating temp. Then when I am driving it will make its way all the way to the Hot and fluctuate but stay really high up near Hot on the gauge.

I checked the signal wire from the sensor on the thermostat housing, this seemed ok. I checked for air bubbles in the system, that checked out ok.

I haven't done anything different in the last few days either.

Any ideas what this could be??

Thanks!

 

this is possibly incorrect and anyone correct me if im wrong but it sounds like the thermostat is going bad maybe staying open or closed for all anyone knows. Just a guess

 

It sounds like your temps are normal, but it's just starting in the wrong place. have you taken your cluster apart lately? maybe check the coolant temp sender too.

 

Thanks for the help guys! I have need taken my cluster out of the car so I'm pretty sure it's not that. I am really leaning toward the temp sender. I am going to go pick up one today and give it a shot.
I will trough it on evoscan also to find out exactly why my temps are when it claims to be overheating.

I will update later today!

 

I installed the new temp switch and I turned the key to the On position and the temp gauge stayed below cold where it should be. I then started the car and let it idle for a few minutes and it slowly started rising.
I will drive the car tomorrow to work for the real test. I will post the results!

 

Everything appears to be back to normal now after changing the temp sensor. YAY! Easy fix.

 

I had the same exact problem today did you replace the sender switch in the front of the thermostat or the temp switch in the rear?

 

The single wire sensor in front is the one for the gauge.