So I had a stripped bolt on my thermostat housing which caused it not to clamp down all the way. So, the gasket blew. I replaced it and the bolt and now my heater hoses aren't getting hot. The rest of the engine stays at operating temperature, doesn't get hot at all. Coolant level is full but I'm getting no heat. It was pretty cold last night so I'm wondering if maybe my heater core turned into ice and therefore can't flow. Or maybe there's just air stuck in it.

How should i go about diagnosing this? I was thinking I'd pull the heater hoses and run water through it. Thoughts?

 

Your thermostat may be installed upside down (backwards)?

 

Even if it was, there should be a little warmth at the heater hoses. Coolant goes through them first. Wouldn't it overheat with an upside-down thermostat?

 

I always thought so.

 

You probably have air stuck in the heater core. To check for air, rev the engine up to about 3000 RPM. If you hear a gurgling sound coming from the glove box area, that's air in your heater core.

To bleed the air out:
1) Remove radiator cap
2) Start truck and let it idle until fully warmed up.
3) Add fluid.
4) Rev the engine and keep adding fluid until it won't take any more.

 

Thanks everyone. I just decided to bounce it off a tree to get the air to shake out. Nice and warm now.

 

Ouch, that really sucks man