temp gauge going high at idle but goes back to normal when runni g

[athan12]

my temp gauge goes up when im on idle or when im stuck in a trafic light.but when i start moving the temp slowly goes back to normal then go high once again when i hit a red light. i guess its only the wind blowing thats cooling my thermostat.

what could be the possible reason on this? driving a 91 automatic

[deevergote]

Does your radiator fan work?
How high does the gauge go?

[athan12]

theres actually two fans in here. the one closer to the coolant works when i turn off the engine. it goes close the red line but never over red. how do i know which ones for the radiator and if it works?

[jewelproject]

sounds like the thermostat needs replacing.

the fan on the passenger side is the radiator fan. the one on the driver side is a/c fan.

you should unplug the fan, the connector is right under the coolant reservoir. just pull up on the reservoir and you will see it.
when you have it unplugged run 12volt power to the connector. i forget which one is + and - but you have 2 guess to find out, sorry.
if it comes on, its good.

but you say the fan does come on when you turn your car off?

[athan12]

yea it does cos i can hear it spinning when i turn off the engine. the person i bought it from replaced the timing belt thermostat and w
ater.pump

[jewelproject]

yea it does cos i can hear it spinning when i turn off the engine. the person i bought it from replaced the timing belt thermostat and w
ater.pump

not being an ass but seeing and hearing is two different observation. you should really make sure it is coming on.

i would suspect a faulty thermostat is your issue even though it has been replaced. not everything new will be 100% perfect. maybe they did change thermostat but not the seal. i could be wrong, but i did just have this similar issue a month ago. a new thermostat and seal fixed the problem. 15 bucks for both parts at the parts store.

[athan12]

my car is blowing white smoke as well and i just failed the smog. planning to change the gasket and see if the temp stays normal.

what do you mean on the thermostat seal? can you elaborate this more to me.

[jewelproject]

my car is blowing white smoke as well and i just failed the smog. planning to change the gasket and see if the temp stays normal.

what do you mean on the thermostat seal? can you elaborate this more to me.

white smoke is not good. head gasket must be on its last leg.

sorry i said seal. i meant gasket. the rubber gasket that goes around the thermostat. always should be changed when thermostat is changed.

actually some call it a gasket seal. thats why i said what i said.

[athan12]

could it be that i need to get my cylinder head resurfaced? thats why the temp gauge is going up?

what are the signs of a warped cylinder head?

[accordjdm7]

The easiest way to tell if your head gasket is bad,
Just open the oil cap in the morning and look at the plug if the oil is colored chocolate, or white is a color in it.

That's the easiest way, the other is:
Uncover the radiator and start the car if it looks bad out many bubbles have your headgasket

spanish
La manera más fácil de saber si su head gasket es malo,
Solo tienes que destapar el tapón del aceite en la mañana y ver en el tapón si el aceite esta color Chocolate, o queda un color blanco en el.

Esa es la manera más fácil, la otra es:
Destapar el radiador y encender el carro si se ve salir muchas burbujas tienes mal tu headgasket

[lilg4mdalbc]

it is possible that you warped the head by alot because i red that you said you didnt let it go over red, which would make me assume that you let it get to red. If thats the case, then you have a lot of work to do. But either way, lets start with the basics. Like jewelproject said, are you sure your fans come on while your car is on? Because theyre are two fan switches: one that turns on the fans while the car is on, and one that turns them on up to 15 minutes after the car has been turned off. Then also check your thermostat. Make sure it's not getting stuck open. Unfortunately, from the looks/sounds of it, because white smoke is coming out of the exhaust, you very possibly need head work done, meaning new headgasket/resurfaced head.

[10thAnnivCB7]

mine does this too but the gauge stays right at 3/4 of the way. No matter how long im in traffic it stays right at 3/4 of the way and when i start moving it goes back down. Fan turns on at idle but seems to not turn on when im in gear. I have more important things to fix now than that.

[cloudasc]

Op, too me it sounds like your lower temp thermo switch has failed.

[oyajicool]

There are two temp probes.
One for normal operation with engine running. "On" temp is 189*f ~ 199*f. "Off" temp is 176*f ~ 196*f.
Like cloud says this one is probably faulty on your car.

Another probe linked with Fan timer which comes to play when ignition is off. "on" temp is 221*f ~ 231*f. "Off" temp is 208*f ~ 228*f.

[10thAnnivCB7]

oh im not blowing white smoke at all so we may be something a loke but not the same problem.