hot but no heat

[poda]

I have a 92 4.0 ranger, and when it's really cold outside around -5 or colder my heater dosen't work. But at the same time the engine is runing very hot, could this be the thermostat?

 

[Wicked_Sludge]

the factory gauge is flunky, id varify the engine is reaching operating temp with an aftermarket gauge or IR thermometer. if it is, probably a plugged heater core. if it isnt, replace the t-stat.

 

[poda]

the factory gauge is flunky, id varify the engine is reaching operating temp with an aftermarket gauge or IR thermometer. if it is, probably a plugged heater core. if it isnt, replace the t-stat.

Yeah it was hot, there was steam coming out from under the hood. I also noticed under the hood that there was coolant everyware around the resivour tank, would this happen because it got really hot? I'm thinking it may be the t stat also, how would I check the heater core to see if it's plugged? thanks!

 

[BlackBII]

You can pull the heater core and run a hose through it, see if it is clogged.

If the fluid is coming out of the resovoir, I would suspect maybe a stuck thermostat, as the fluid may not be circulating, over heating the truck.

 

[cocoasranger]

Check the radiator cap. If it is weak and/or has a bad seal it can both leak coolant like you describe and also not allow pressure to build up in the system which reduces heat transfer and efficiency. It's cheap insurance to put on a new cap if you are not sure how good the present one is, plus it only takes a few seconds to install.

 

[Doofy]

Check your glycol protection level. May not be rated down to the outside temperatures you are experiencing.

 

[poda]

Well I found the problem, the radiator is split along the plastic seams, causing it to overheat and the heat not to work. Thanks for all the info, and tips!