No heat, but All Vents and everything else is working

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JohnMcD348

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OK, I just noticed this morning that my heat really doesn't work anymore. I had my system replaced about 3 or 4 years ago, after my A/C went out, so I now have the "newer" updated system behind the dash with the improved doors.
When I adjust the vent settings, they all move appropriately to the proper vents.
When I turn off the A/C, the air blows at ambient temps, maybe 5*-10* hotter, but nothing like the Heat
Engine runs fine, temp stays between 190-210*.
I checked my engine bay heater hoses and both sides feel hot.

Can it be possible that the heater core is blocked and hot water is just "stuck" in both lines? I would think one side would be cooler than the other is the core were clogged.

What else should I be looking at?

Thanks

John
 

Jason G Slabaugh

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Try a new thermostat, could be stuck in the open position. Also do a good radiator and system flush on it. Could have some gunk stuck in there too
 

TMyers

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Pull a vacuum on the system and add some coolant. If the system has any air in it, it's in the heater core.
 
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JohnMcD348

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Thanks.

I've never done that to a coolant system before. Done it a few times with the A/C systems, but never a wet system. I'll have to google how to do that.
 

Fast69Mopar

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Thanks.

I've never done that to a coolant system before. Done it a few times with the A/C systems, but never a wet system. I'll have to google how to do that.

Are you sure that you hear the blend door moving when operating the temperature control knob?

If both lines or the heater core are hot then you should have heat. Now, on the other hand, if the heater core has a restriction, eventually the outlet side of the heater core will get hot because the coolant in the motor is getting hot and the heat will eventually transfer up the hose.

An easy test would be to let it sit overnight and go through a cold soak. Start the engine and let it run. Make sure the blower motor is turned off. Feel the inlet side hose and the outlet side hose to monitor the temps. They should both stay really close to the same temps while the engine is warming up. If the inlet side is getting hot while the outlet is staying cool then you have a restriction. If they are both really close to the same temp then some more diagnostics are in order.

If you really want to verify if the heater core is restricted or not, remove both heater hoses while the engine is cold. Stick your water hose onto the heater core and turn the water on and monitor what comes out of the outlet.
 
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