Heater Problem
 

Hey guys it's cold here in Ohio and my heater is not working. I've never worked on the heater before. It's blowing air, but it's not hot air. There is plenty of fluid in the radiator and I've put new heater hoses on. Obviously there is an issue with the heater itself, but I don't know how to trouble shoot it.
Any help would be appreciated.
Thanks,

Re: Heater Problem
 

The engine does have a thermostat in it? To get the water temp up high enough so that the heater will throw off decent heat and the engine will operate better.

First get the engine up to operating temp and put you hand on both hoses one at a time. Are they both hot? the inside of the heater core may be partially blocked.

On that truck it's easier to pull the hoses of the engine and then backflush the heater core with a water hose. What you do is put the hose up to the hose that came off the water pump and flush water though the heater core until it shows clear than go to the other hose (or outlet on the heater) and flush the other way. You keep going back and forth until you don't have any crud coming out with the water. The other way would be to have someone power flush the cooling system.

If you aren't getting good air flow there may be something clogging the air flow though the heater like a mouse nest. I need to pull the heater out of my 71 GMC and clean out what a mouse put in there when the truck was sitting a few years ago.

Also someone didn't happen to put a shut off valve on the outlet from the head to the heater? A lot of guys did that to shut the water flow off in the summer to get it a little cooler in the cab.

Re: Heater Problem
 

Pull the hoses from the heater core and back flush the core. You can blow a light amount of compressed air through the core , but not 100psi or it may damage it. Sounds like the core is blocked. If you cant clean it, replace it.

Edit: Mr48chrv and I posted at the same time....follow his post, mine is the same theory, his is better.

Re: Heater Problem
 

Did you pull the heater box and clean it out? On my TF every fall I had to pull the box and dig out all the leaves,pine needles, etc. that got suck in the outside vents and clogged the core and passages. I have never had a Chevy with a good heater that would not create a cab sauna.

Re: Heater Problem
 

The AD trucks don't have the air intake on top of the cowl Orrie but that doesn't mean that a critter didn't decide that Wayne's beast's heater wasn't a great place for a nest at one time. If it is blowing a lot of air that isn't the problem though.

Re: Heater Problem
 

Nicely said :lol:

Re: Heater Problem
 

in my 57 - i went thru my heater top to bottom - and OrrieG is correct they are v efficient - even here in sin city it gets a ''bit'' chilly and it will cook ya .

Re: Heater Problem
 

Couldn't have asked for better advice. Thanks for your help. As soon as we dig ourselves out of this winter storm I'll get to working on it.
Thanks, Again.

Re: Heater Problem
 

Thanks guys for your help with my heater problem. Looks like the thermostat was sticking. When my temperature gauge would go above 150 I would turn on the electric fan allowing for the temperature to go back down. Never thought the thermostat was bad. So I was actually hiding the real problem.

Re: Heater Problem
 

Thanks for posting your findings and glad you got it working.