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1987 cherokee heater problem!!

1

1987jeepxj

NAXJA Forum User
Location
hanover park, illinois
i just bought a 1987 jeep xj with the 4.0 and the heater blows but it just blows cold no matter how hat the truck is!! does any one have an idea of what this could be it would help me alot!!
 
1987jeepxj said:
i just bought a 1987 jeep xj with the 4.0 and the heater blows but it just blows cold no matter how hat the truck is!! does any one have an idea of what this could be it would help me alot!!
Click to expand...
check under the hood, where the heater lines go into the firewall on the passenger side, there is a plastic valve with a vacuum line going to it. For some reason I have to unplug my vacuum line and block it off in the winter to get heat.
 
The heater valve is supposed to default to open (with a lack of vacuum = opened)

But I suppose if it is really old it could have got jammed from the winter months of being closed. Or a chunk of plastic off of one of the lines could have broken off and jammed inside of the valve, it is common for the plastic to crack with age.
 
Very common problem on erly xj is build up of crud in heater core.A good flush will most often cure the problem.Has worked for me on more than not.
 
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