heater issues

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scrap--metal

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fender89

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Hahah yes I assumed it was could of sworn it was cold when the engine was running. But at this point I'm not sure what else to check
 

fast 99

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If the core is out replace it with aluminum. They are much more efficient. I keep saying it one this site, buy a cheap heat gun. They cost around $20 today. It is really hard to diagnose a heater problem without some actual numbers like the temperature of thermostat housing, difference between inlet and outlet hose temps at core.
 

fender89

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Well.... I think I found the problem the thermostat was stuck open ... Thank you to 85k30 even tho I didn't take the advice initially..I had just replaced the thermostat about a year ago. I also could of sworn I felt the upper rad hose was cold after the truck had been running a while but I guess not. Anyway thanks for the advice fellas
 

SquareRoot

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so now that its -15 out i guess i need heat. only blowing lukewarm out of vents. i checked coolant levels are good. top of the radiator. both hoses running to the core are hot. i took them off today and flushed out both ways. still not blowing anything but lukewarm. from my understanding its a super simple design, hot coolant flows thru a radiatior, fan blows over it and creates heat. if when i flush it comes out both ways just fine where is the problem?Yo
Your location says central AZ and it's -15? Damn!
 

Camar068

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Well.... I think I found the problem the thermostat was stuck open ... Thank you to 85k30 even tho I didn't take the advice initially..I had just replaced the thermostat about a year ago. I also could of sworn I felt the upper rad hose was cold after the truck had been running a while but I guess not. Anyway thanks for the advice fellas
Good info, didn't know that. TY @85K304SPD as well. lol if I did know it, dun forgot.
 

85K304SPD

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I had this happen one time with one of those "fail safe" thermostats in my Jeep, on a deer hunting trip. The thermostat got locked in the open position, and it never got hot enough to heat the heater core up. No more of those "fail safe" in any of my vehicles.
 

potent rodent

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how did u test it did u take it out and put it in a panof boiling water an see if it open up ?
 

GARY l

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so now that its -15 out i guess i need heat. only blowing lukewarm out of vents. i checked coolant levels are good. top of the radiator. both hoses running to the core are hot. i took them off today and flushed out both ways. still not blowing anything but lukewarm. from my understanding its a super simple design, hot coolant flows thru a radiatior, fan blows over it and creates heat. if when i flush it comes out both ways just fine where is the problem. I had the same problem it was a vacuum hose that wasn't plugged in.
 

GARY l

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it's a vacuum issue, check the vacuum line that connects to your center actuator you'll find it just left of your floor vent up behind the duct it might be unplugged.
 

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