Help! Car only heats when sitting still!

[Austere579]

My '97 Camry will heat up some when sitting still, but in motion will not heat up. My readout registers it heating up when idling, but stays on "C" (cold) no matter how far I drive. It is only blowing cold air. What should I do?

[sbushnak]

Could be the thermostat. When was it last changed?

[davemac2]

sounds like the thermostat is either stuck open or is missing.

dave mc

[Dave's]

I'd most likely change the t-stat too. Sitting still the only airflow over/through the radiator is from the fan(s). Moving you get much more air flow and in the cold of winter it only adds to the cooling effect. The t-stat is meant to restrict coolant flow through the radiator until the correct temp is reached and it doesn't sound like this is happening. You can sometimes check this by removing the radiator cap (best done before engine has been run and is cold or you risk injury from hot, pressurized coolant spewing out) and then starting the engine. You should see virtually no coolant movement in the radiator (other than from engine vibration) until the engine has warmed up and the t-stat has opened. This could take ~5-15 minutes at idle normally and the flow will increase as the t-stat reaches max open. DISCLAIMER: NEVER open a coolant system when hot even if the gauge doesn't show it as hot! Serious burns and other injuries could result. With the cap off while cold there should be no pressure build-up from idling the engine so there SHOULD be no danger in the above procedure but if you do so it is at your own risk. And stay clear of the fans as they may start unexpectedly. Anything else guys/girls???