2003 Ram 1500 3.7 Heater not working!

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Skatulaki

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2002 1500
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5.9 liter 360
I recently bought this used 2003 Ram 1500 with 3.7, Been driving it for a while and really like it, now that the weather has become colder, I've discovered that the heater is not working. Any help appreciated TIA !

What I don't know: is how the system is meant to operate.

What I have heard: is that there is a valve that opens the water to the heater core, that can get stuck or lose vacume and not operate, and that there is a door that breaks the plastic pins.

What I do know: is the A/C works, but the air flow is not as good as it should be, but I get zero heat when switching A/C off and turning to defrost heat. When I turn the knob from cool to heat, I don't hear any sort of mechanism engage to alter a change. When I bought it I knew it had a bad head gasket, and I guess acting cheapskate I poured head gasket sealer in it. While it did and still does appear to have sealed the head gasket leak. I shortly after had overheating problems, the radiator swelled, and the water pump blew out its gasket, and it turned out the previous owner had rigged in an electric fan and removed the mechanical one. I was aware of the electrical fan when I bought it. I also had a pair of sunglasses fall into the driver windshield vent, which I have not retrieved yet.

What I have done: New radiator, new water pump, electrical fan wasn't working, removed it and reinstalled an original mechanical fan, while I still need a shroud extender it seems to be cooling just fine. I removed the fan and resistor, and found what seemed like a birds nest of leaves and trash and cleaned this all out and got improved air flow, yet zero heat.

I suspect a bad mechanism, but cannot rule out the gasket sealer clogging up my heater core. A friend told me a clogged heater core can be blown clear using pressure washer.

I'm about to dive in and see what's going on, but it's also my daily, so I don't want to go too far yet, any and all help appreciated ! TIA
 

GTyankee

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First, there are two hoses that go through the firewall on the passenger side

With the heat turned full on after driving it
Both Hoses should be Hot, but one of them should Hotter.

If you unfasten both hoses & put Low pressure Air or Water through the cooler one, then the hotter one
Hopefully something will flow out until the water becomes clear & the flow is steady

Hopefully no one ever ran the wrong coolant in the system
 
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Skatulaki

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Well the other morning when I drove to work I turned the heat on and not one breath of warm air, so I check the hoses, neither was hot, nor seemed to have pressure. Before I drove back home I checked coolant level, and to my surprise, there wasn't hardly any in it. Where did it all go? No leaks, not in oil pan, and it was fine a couple months ago. So I refill the system, and the next going to work, it was just enough warmer to keep the lower portion of windshield from fogging over. I check the hoses again one is hot, the other warm but not hot.
So, the mystery of dissappearing cooling fluid. It occurred to me that after school reopended and with all the development that has gone on. The roads are unable to handle traffic volume so I've been in massive traffic jams all fall. The only thing I can figure, is without the shroud extension ( for the V6 ) It's running hotter than normal, and the stuff just steamed slowly out of the overflow hose.
I haven't yet tried to flush it, and I read somewhere there could be air bubble. However in Florida there are no steep hills anywhere. When I refilled it, I kept pouring it in while running until it started expanding.
This is as far as I've got.
 

jws123

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You could put some uv dye in the coolant system for hard to find leaks then use a uv light.
 
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Skatulaki

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Been a while since I've been able to get back. In the mean time I've been adding oil and water and working hours. Today I finally get opportunity to again look into this, and I find out that you have to bleed the system. There is a hex screw near the alternator where the radiator hose connects to the engine. One is supposed to loosen this up quite a bit so that liquid is coming out. Then crank up the engine and let the air bubble out. What I haven't been able to find out is how long this is supposed to take. I ran it up to temp and it was still bubbling out so i ran it a while longer and when I saw steam coming out of the overflow, I capped it off to see if adding pressure would get more out, well yes it became almost foaming, I ran it like that for quite a while looking back and forth at temp gauge, it was staying below centerline, which it never did before. ( I just got it last summer and have been getting it back in working order, I've had to mainly work on cooling system ) It used to just keep creeping up without airflow. It usually stayed around centerline, unless not moving, then it would creep up.
Well I'm on E so I shut it off and closed the hex plug, It was still foaming. No noticeable change with heater. I'm resigned to having to change out the heater core, though I'm going to try and Flush it out first.
 
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Skatulaki

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Ok back at it again today, disconnected the heater core hoses on the water pump end, sprayed water hose into both hoses, praying into the upper hose I got some water flow out of the other but most of it backed out under the nozzle so I tried it the other way and got a trickle out of the top hose and it seemed to keep taking more, when I moved the hose a lot came back out, and I realized most of it was going back up into the over flow. Not satisfied with this, I connected a garden hose fitting to the upper hose, and got lots of water flow out of the lower hose ( that is connected to the overflow ) so Im satisfied that I have adequate flow through the heater core and don't have to replace it. Going to put it back together and see what happens.
 
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