Heaters not hot...

[fiscus]

I haven't been driving my MJ as much since the cold hit here in Ohio since the heater doesn't blow hot.

 

I would assume it has a thermostat (though this isnt verified & it only has idiot lights, not temp guage), but letting it sit & run does nothing for making it hotter. I would assume this means it's not the thermostat.

 

It originally had a heater control valve, but it was bypassed at some time by the PO, it is just hanging under the hood. All hoses are (supposedly) hooked up correctly.

 

The heater controls appear to be working correctly. It has 3 or 4 different speeds/settings for blowing that work & it switches from floor/vent/defroster fine.

 

Does this mean a clogged heater core or is there another valve somewhere that could be bad?

[offroader461]

personally i would hook the valve back up and reattach the vacuum line that controls how much coolant gets to the heater core....at worst it could be a clogged heater core

[Oizarod115]

personally i would hook the valve back up and reattach the vacuum line that controls how much coolant gets to the heater core....at worst it could be a clogged heater core

 

where is this vacuum line you speak of? my heater doenst blow nearly as hot as my bros or moms. but I'm sure none of the valves were messed with by the PO.

[Mitch]

I would guess thermostat or heater core, start with the thermostat because its cheap and easy.

[offroader461]

there is a plastic line that comes out underneath the overflow bottle and connects to the bypass valve and that is what controls the flow to the heater core

[87manche]

there is a plastic line that comes out underneath the overflow bottle and connects to the bypass valve and that is what controls the flow to the heater core

FWIW that vacuum hose on my rig is a light purplish.

[Oizarod115]

when you talk about thermostat, do you mean the coolant thermostat, like the one up front by the serpentine?

 

cause i know that's not the problem.

[carnuck]

Do you have a dent in the passenger's side of the bumper? That's where the vacuum reservoir is (stupid design!) The other is the vacuum "motor" right above the gas pedal has the hose come off when you push your foot up too high.

[Oizarod115]

Do you have a dent in the passenger's side of the bumper? That's where the vacuum reservoir is (stupid design!) The other is the vacuum "motor" right above the gas pedal has the hose come off when you push your foot up too high.

 

ill check the one near the pedal... I'm pretty sure i hooked the resovior up right last time i took the bumper off, never hurts to check though

 

thanks.