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Heater not blowing hot?

R

rockcrusher

NAXJA Forum User
Location
georgia
I know it summer but I would like to get everything working before it get cold outside. My a/c works fine blows ice cold but when i turn the heater on it blows warm not hot at all. I just put a new motor in and i was having overheating issues now everything is fine. Temp stays between 200 and 210. with the a/c on or off . Back when it was over heating i could move the temp select switch over to the hot side and it was very very hot. and now its not doing that. I have not changed any thing so im confused. My xj is 89 4.0 AW4 242 if that helps at all. Thanks for any help.
 
Before tearing apart the dashboard and whatnot to get at your heater core, try checking the heater control valve to see if it's actuating... I agree it's likely clogged but why not try the easy stuff first? Look for a small four port valve connected to the two small hoses running along the passenger side of the engine block. See if the actuator coming out of the vacuum solenoid is actually moving in and out, and check the vacuum hose going to it - should take about 5 minutes.
 
Cool I'm always like to do the easy things first . I just thought about it i dont have that valve i have the vacum hose but the bypass isnt there somone had bypassed that valve. So shouldnt there always be hot water going to the heater core.
 
Last edited:
Ah, yeah in your case you don't need to check at all... so much for easy. Maybe try feeling the return line after the engine's been running a while and see how warm it is? Sounds like your core is clogged for sure though...
 
Do you think that I can take the hoses off and flush it that way, or do i need to replace? I guess that it wouldnt hurt to try to flush with water hose. all it can do is break the heater core. LOL
 
rockcrusher said:
Do you think that I can take the hoses off and flush it that way, or do i need to replace? I guess that it wouldnt hurt to try to flush with water hose. all it can do is break the heater core. LOL
Click to expand...
Go for it, just don't overdo the pressure... last thing you want is to pop a marginal piece of tubing in the core and fill your dashboard/carpet with coolant, sludge, and water from the garden hose! If you reverse the direction of flow (try both, whichever knocks more crap out of it is reverse) it should clear it out pretty good like bigalpha said.
 
Well I checked the temp of both hoses in and out and are both hot. So now what? maybe a vacuum lines on the temp control? Im lost thanks for the info
 
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