my truck is overheating when it idles
when you run the rpms up to 1500 or so it goes back to normal
also when it starts to over heat cold are starts to come out instead of hot air but when you run the rpms up hot air starts to come
wonderin if it is the thermostat

 

Kelly,

First run a Search, as this is a topic that`s been covered before.

Sounds to me like it`s either the thermostat, or a blockage in the heater core or one of your hoses. You would definitely need to troubleshoot it.

You could start by letting the engine idle up to operating temperature for a few minutes, then touch each hose. If the hose is hot, then antifreeze is running through it. If it`s cold, then there`s a blockage. If you find no blockages, replace the thermostat. It`s a pretty quick and easy repair.

If you DO find a blockage, then the location of the blockage is what you should be concerned about. If it`s near the water pump, then that may need replacing. If it`s near the heater core, then that may be the problem. You could try disconnecting the problem hose and try running water through it. Search for other threads for more detailed information on how to do this.