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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: mikewb on December 19, 2008, 02:49:14 pm
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Hey guys i need some ideas. I got a 82 swb chevy half ton. havent been able to get heat. Thought core was plugged soo i bought a brand new one and put it in yesterday still nothin. I thought might be the doors not opening and closing correct under the dash soo i took part off the front and moved then with my hands to see if there was hear coming out of there at all and theres not. The hoses are warm to touch but not hot. Cant figure out what else could be. Is it better to have the engine hose run off the intake or water pump?
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are you sure you even have a thermostat on your engine?
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Yeah. I checked to see if there was one and its in there. but i dont know what size
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would a different thermostat let it get hotter?
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the thermostadt might be stuck open. Therefore not closing to allow engine to warm propertly, therefore, not having much heat/defrost.
Put another tstadt in there, they are cheap. Ensure one hose going to heater core is hot, the return should not be as hot.
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Both hoses are just barely hot. I can hold them without any problem
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Put a 195° T-stat in it
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is that bigger then normal? whats the biggest one?
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I wouldn't describe it as "bigger" but normal tstadt is 180. a 195 will bump the temp up prior to opening up. A new tstadt will keep the temp where it supposed to be. When you take the old one out, note the spring on it and if it is compressed, that keeps it open and the antifreeze is just free flowing no matter the temp.
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195° is factory.
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That the hottest one you can get?
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No but you don't need or want hotter than that. Just replace yours. I replace mine every year.
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Ok boys, I got a new thermostat and heater core. And still no heat. What else might it be? It doesnt even blow warm air.
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Are the hoses to the heater core hot?
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I am assuming you did this after replacing the tstadt, but, ensure your antifreeze level in radiator is good. That is the blood of the heater system.
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Theyre never really hot. just a little warm.
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So the core ain't getting hot? whats the running temp of the truck?
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take a pic of how your hoses are routed. Feel along the hose coming from the intake manifold and see if there is a cold spot.
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where does the outside air come from? It seems like theres cold air being blown in even when the heaters not on
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Air comes in through the cowl.
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soo there q way it could be stuck open? or is that normal?
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where does the outside air come from?
vent is stuck open. Check your cables that operate the heater plenum...the A/C, heater, vent, defrost controls.
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Take the dash out to see whats goin on? or whats the best way to see
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Mikewb did you read my reply?
How are your hoses routed? Are they hot anywhere along the way?
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the one coming from the pump is warm all the way up. and the other is just barely warm going to the radiator.
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Mikewb did you read my reply?
How are your hoses routed?
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is there a valve installed on one of your heater hoses and maybe the valve is shut therefore no coolant if flowing through which would lead to you not having any heat?
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i was thinking heater control valve also but not even sure if its and option on them old trucks. we need pics. you have vents on the kick panel. i had to block mine off cause it was just sucking in cold air
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one comes from the water pump and goes to the core. and the other comes out and goes to the radiator
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now i maybe wrong but there is more than one flap on the trucks like the temp. flap no ideal what its called lol and the flap to control floor, face and defrost. when you checked the flaps was the one you checked on the floor?
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yes. they all work but blow cold air. the one on the floor blows the hardest tho
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bottom line is this: the input hose, going to the cowl, should be hot, hot to the touch when engine is operating temp. The return hose should not be as hot, if heater core is working properly. On my '79, the upper hose goes to radiator, the lower hose goes to intake.
I assume yours should be the same way.
(http://www.delbridge.net/heaterhoses33.jpg)
(http://www.delbridge.net/heaterhoses44.jpg)
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Yea. I know what it SHOULD be doing. Just dont know why it isnt. They are routed the same
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is this when your driving or just sitting