I own a 99 Accord and recently noticed that when my car is idle that my temperature gauge starts to rise 3/4 of the way to Hot. This could not be normal as the temperature should be somewhere in between C and H right. Once I turn the ac on, the needle drops back down and to normal which is between H and C.

Does anybody know what could be at fault with the temperature gauge when idle? Thanks!

 

sounds like you have a busted thermostat. when my 6th gen is completely warmed up, it's a little under the half way point.

 

well when the car is at an idle... and the car is not moving, of course the engine is going to get a little hotter... as there is not any air flow to cool the engine. When you turn the A/C on, the fans kick on, cooling the engine down.

Just check your coolant, and make sure that the fan turns on automatically when the temperature rises... if not, the fan temperature sensor or relay maybe bad. Only one fan turns on when the temperature rises, both fans come on when the A/C is on.

 

Thanks for the replies. Could it be the radiator fluid needs to be flushed?

 

possibly

 

very possible... when the anit-freeze gets old and breaks down, it starts losing its ability to transfer heat... so a flush and re-fill maybe in order for you.

 

Your fan switch could have also gone bad. You have two fans to cool your engine. One turns on when you are sitting in traffic, it should kick the fan on when the temp hits like 180 degree's. The engine cools down when you turn on the A/C because your other fan is coming on.

Stop and get your fan switch checked.

At least that is what happened to me, my car would only start to heat up when I was in really slow moving traffic or I was stopped.

 

yes....have a shop check it out. Its hard to find the actual cause when there can be so many parts that can be malfunctioning. My money is on the thermostat!

Dave

 

Check the wiring before changing the temp sensor.

 

When you check your collant level, if it is low

it could be the heater core leaking

instead of going through the process of replacing the core I just capped it off and routed the hose back

but only do it in a warm climate