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97 country, heat issues

bgwyllys61

NAXJA Forum User
Location
kentucky
well, i have a new water pump, thermostat is a yr old, and my blows, well, luke warm i guess....i cant find a control valve like the older xjs had, so im assuming this one works off vacuum? why would it not blow hot even though my operating temp is nice and warm? the heater hoses going to and from the heater core are hot, but its not hot air coming out inside, what should i check?
 
unhook your hoses from where they go into the firewall, take a hose and see if water will move freely through it. im guessing your heater core is prolly clogged up a bit. you can flush it through both connections and hopefully dislodge the buildup of stuff in there. if that doesnt work, go buy a small container of vinegar, put it in your cooling system and run it for a while to work it through the heater core...i ended up letting mine sit over night it was so bad. then just flush it out really good. it sounds like more work than it is, but its really easy to do. hope this helps
 
Definitely could be a clogged heater core as jmeti000 mentioned. I'd start by flushing it and see if that helps. Can do so with a garden hose. Flushing a heater core is easy, replacing it is NOT! :nosmile:
 
thanks guys, i definately dont want to go through the hassle of tearing into all the dash and stuff to replace it, ill try flushing it when i get back in town
 
No heater valve on 97+'s, coolant flows through the heater core full time on 97+.

My guess is a blend door problem maybe, or a stuck open thermostat or something. Since coolant is constantly flowing through the core in 97+ there isn't any time for it to sit and sludge or clog up like in older XJ's during the summer months when heat is not used.
 
No heater valve on 97+'s, coolant flows through the heater core full time on 97+.

My guess is a blend door problem maybe, or a stuck open thermostat or something. Since coolant is constantly flowing through the core in 97+ there isn't any time for it to sit and sludge or clog up like in older XJ's during the summer months when heat is not used.

Where is this blend door and how do I go about checking it?
 
The blend door is controlled by a cable that is attached to the back of the temp control on the hvac panel, at least thats how my 98 is setup. I've heard that 2000+ are electric controlled for that, no cable. The cable has clips on the ends that keep it in place. If you remove the knee panel under the steering wheel you can see the heater box.

Word of caution, if you do decide to flush it use a garden hose but DO NOT seal that hose nozzle to the core, your house water pressure is usually over 50PSI, the cooling system runs at 16psi, if you over pressure the core you will probably blow it out. The upside is you will be forced to learn how to take the dash apart to replace the core....
 
Flushing the heater core fixed mine. It was pretty clogged in one direction, and one hose never got as hot as the other one. I flushed it out in both directions and I have good heat now.
Thanks!
 
thanks guys, i definately dont want to go through the hassle of tearing into all the dash and stuff to replace it, ill try flushing it when i get back in town
What'd you find out? Do you have the toasty stuff now :)?
 
I had the same thing going on with mine. (97) Luke warm heat, barley enough to take the ice chill out the air and certainly not enough to heat the inside. Flushed the heater core for some time, swapping between hoses. had the water running clear. I kept my eye on the stuff coming out and noticed only a small amount of crud came out. (2 or 3 seconds worth at most) I assumed it couldnt have been enough to cause a blockage and feared the worst. However i also made sure the coolant was topped up fully by parking it up a steep hill. Either way I had heat after that.
 
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