Temperature gauge fluctuating
 

I have a 2004 civic automatic, I've had this problem since August, on and off. My temp gauge will raise quickly, and recently stays on H for awhile, but it is cold outside and I don't believe it could heat up that quickly to overheat. It used to fluctuate between C and 3/4 to H. Also, my car won't be heated up enough to even blow hot air when the heater is on so I don't get how it could overheat. No engine lights come on, no smoke or smell when it goes to H, and I checked under the hood and it wasn't hot. I've had the thermostat and fan switch replaced twice, radiator checked out, several diagnostics, one place told me it was the head gasket, another checked it and said it wasn't. I don't know what to do, it does this every day now and I'm scared to drive my car but I feel like it is not actually overheating but possibly electrical? Input greatly appreciated

Re: Temperature gauge fluctuating
 

Here's a novel idea:
Troubleshoot the gauge, its sending unit, and its wiring.

What does a scanner say the engine temp is, while the gauge is acting up?

Re: Temperature gauge fluctuating
 

If it really IS overheating at this point you have a bad headgasket.

You need a better mechanic.

Re: Temperature gauge fluctuating
 

Thanks for the input it is appreciated, the thing is I've been to two different repair shops and a honda dealership, who have all told me different things. We're going to test the actual temp tomorrow

Re: Temperature gauge fluctuating
 

I can't believe I'm not the one that said this.

Re: Temperature gauge fluctuating
 

Heck, I am not even a mechanic, and I can figure it out with a scanner and some time.

If it really is overheating, your coolant tank should be overflowing everywhere. If its not then chances are you have a bad gauge/wiring.