Temperature gauge stopped working

Hi,
When I start my malibu and dive it my temperature gauge will go up to 2/3 wich is to hot, after it hits the 2/3 it will go right back down to the normal 1/2 way mark while its going up I have very little to no heat coming out of my fan.
I recently had my thermostat changed because of simmilair issues and it was working fine for about 3 weeks, now its acting up again.
I watcehd my mechanic change the thermostat and he did "burp" the system and all tht. What is probably the cause of this? The ca has about 200000 km on it

I don't seem to be loosing any coolant, im gonna double check tho and I checked for the common signs of a head gasket problem ( dirty oil white smoke etc) and thts all fine. Could it have anything to do with the thermostat tht got replaced like I said it was doing great up untill after 3 weeks I had it replaced I apreciate the response

Allright I double checked and there was some coolant gone, I topped it up and drove it and the temperature kept around the halfway mark, still moving up and down but no overheating. I guess I have a leak somewhere eh, so if anyone has to guess where would it be I know the malibu is known for this problem, I did check the oil and stuff again and its clean, the car isnt skipping a beat or nothing so I think (hope) we can rule out the head gasket, also would it be wise to add a liquid sealer maybe to the coolant?

Hello again,
Ok ive kept filling it allthough there was hardly any if at all coolant missing and when hot I smelled nothing under the hood or in the car, another weird thing happened though I was driving it yesterday on my way to town the temperature gauge was doing its funky thing again, I could feel cold air flowing so I knew it was going up, but this time it whent all the way up till the overheat light came on, I pulled off the highway and stopped the car immediately and popped the hood, when I opened it I was expecting a lot of heat coming towards me but this wasnt the case, I could touch the engine it was warm but not hot it was warm as to be expected from a 15 minute drive, I squeezed the radiatore hose and again it was warm but not burning hot as to be expected from an overheated engine.
I brought it in to my mechanic shop and he looked and try to figure out wat the problem was. He couldnt tell me he said it might be the head gasket still but he said then the engine would feel a lot hotter. I dont even know what it could be its a mystery to me, and any help is apreciated a lot. Thanks in advance ! Also the gauge seems to be moving more when I have the hot air blowing then when I have the colder air going

While driving on the freeway, I noticed my temperature gauge dropped to zero. I pulled off and checked my fluid, fans, and belt and all were okay. When I turned it back on, I noticed the gauge would rise slightly and drop back to zero. This happened several times.

When I got to my destination, I used my remote to lock my doors and, although the doors lock and unlock, the horn stopped reporting and the lights did not flash.

On my way home, I noticed that the gauge started working properly. After I shut of the car and remotely locked it, the lights and horn began to work during remote lock/unlock.

I believe there might be a bad connection, maybe, but where would I look that would have both the temperature gauge and remote locking system in common? Computer?

Thanks for the help.

I am not one for coincidences when working with components on a car. That is why I asked. When 2 apparently different circuits fail at roughly the same time, and then without warning, begin working at roughly the same time, I begin to look to see if/what they have in common.

I've been driving my car for almost 3 days now without a failure, so diagnosis is rough and the schematics in my Haynes manual are next to useless.

Thanks for the help and maybe if it begins to fail again, I'll try your suggestions!

Keep up with the good work!

Hello I have a 2001 chevy malibu v6 3100 engine check engine light came on and temp gauge stoped working the cooling fans come on and stay on as soon as I start the car I replaced the temp sencor and it does the samething any ideas?
Thanks
Dan

Yes they had it scanned and they said code was bad sending unit changed it and it made no difference
Thanks
Dan

My heat gauge keeps going out on me and I have to disconnect the battery everytime it does this so it will work again