2000 XJ runs cold, no heat
12-06-2012, 04:30 PM
#17
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Year: 1998
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Engine: 4.0L HO
Hi guys, need a little help..I recently had to start driving a '00 that's been sitting in my driveway for about a year. Everything was fine for a few days, then noticed the temp gauge drop to about 180 while driving, also lost cabin heat. Checked coolant level, it's fine. Flushed cooling system, flushed heater core, good flow out of out both ways, changed thermostat even though it was new. Same results.
If I let it idle it will climb to 210, but still no heat. Upper and lower rad. Hoses are hot, heater core hoses are not, so no flow...but why?? Rad. cap also not hot to the touch, but again level checks fine. What am I missing?
If I let it idle it will climb to 210, but still no heat. Upper and lower rad. Hoses are hot, heater core hoses are not, so no flow...but why?? Rad. cap also not hot to the touch, but again level checks fine. What am I missing?
12-06-2012, 04:56 PM
#18
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I have a similar situation. New water pump, thermostat, did the flush and my heat just doesn't seem very hot. Gauge shows a needle width below 210 at operating temp. I'm getting heat....just not as hot as I THINK it should be. It should run me out at full blast.
12-06-2012, 05:35 PM
#19
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Year: 1998
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FWIW......the heater performance guideline in the FSM is.....with vent selector set on floor vent (not bi-level, not floor and windshield), motor at operating temp (whatever that is), ambient at 60F, floor vent temp should be minimum 144F. My presumption is, if ambient is below 60F, then floor vent temp something a little less than 144F would be acceptable.....if ambient is above 60F, then floor vent temp above 144F is acceptable.
Last edited by djb383; 12-06-2012 at 05:47 PM.
12-06-2012, 08:37 PM
#20
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It sounds like the OP did his flush directly thru the heater core (pressurized water in 1 heater hose and saw good flow out the other heater hose, I presume).....did u do flush your heater core the same way?
FWIW......the heater performance guideline in the FSM is.....with vent selector set on floor vent (not bi-level, not floor and windshield), motor at operating temp (whatever that is), ambient at 60F, floor vent temp should be minimum 144F. My presumption is, if ambient is below 60F, then floor vent temp something a little less than 144F would be acceptable.....if ambient is above 60F, then floor vent temp above 144F is acceptable.
FWIW......the heater performance guideline in the FSM is.....with vent selector set on floor vent (not bi-level, not floor and windshield), motor at operating temp (whatever that is), ambient at 60F, floor vent temp should be minimum 144F. My presumption is, if ambient is below 60F, then floor vent temp something a little less than 144F would be acceptable.....if ambient is above 60F, then floor vent temp above 144F is acceptable.
hmm. Mine was more a generic coolant flush through the upper heater hose(some nasty stuff came out) I will have to do the core only flush and see where that gets me.
12-06-2012, 09:03 PM
#22
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Year: 2000
Model: Cherokee
Engine: 4.0
If you read the first post he already said that he has changed it.
If you are not getting any heat conducting off of the coolant hoses to your heater box I would double check to insure that you are getting sufficiant flow. As in fast enough that the box doesnt cool it down to much before it comes back out.
You also didnt say where you got the water pump from but have personally had bad experiances with having to pull of and replace brand new water pumps before i even get a chance to test drive the vehicle. So I would check the pump next. Good luck. Its starting to get cold.
If you are not getting any heat conducting off of the coolant hoses to your heater box I would double check to insure that you are getting sufficiant flow. As in fast enough that the box doesnt cool it down to much before it comes back out.
You also didnt say where you got the water pump from but have personally had bad experiances with having to pull of and replace brand new water pumps before i even get a chance to test drive the vehicle. So I would check the pump next. Good luck. Its starting to get cold.
12-06-2012, 09:41 PM
#23
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Year: 1998
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Even at 180F coolant temp (as stated in the OP and presume the gauge is somewhere close to accurate) the heater should make u sweat......so it sounds like the t-stat is doing it's job for the most part. Wonder if there is one of those "fail-safe" stats involved here? Talk about some marketing/advertising dept. hype.
12-07-2012, 12:33 AM
#24
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Thanks for all the advice folks...i'm leaning in the diction of the blend door, haven't been able to check it yet though. I assume it is vacuum controlled like everything else? Also I was under the impression that that door just directed air from the hot or cool side of the HVAC box...does it also actually control flow to the heater core?
I did flush the core directly, pressurized water in one heater hose, good flow out the other. Have now had two brand new thermostats in it, and one used known good one stolen from my recently wrecked '01. All seem to be working. Temp comes up at normal speed, levels off between 210 and the next lower hash mark. Just no flow to dash.
Anyone know a good way to access the blend door?
I did flush the core directly, pressurized water in one heater hose, good flow out the other. Have now had two brand new thermostats in it, and one used known good one stolen from my recently wrecked '01. All seem to be working. Temp comes up at normal speed, levels off between 210 and the next lower hash mark. Just no flow to dash.
Anyone know a good way to access the blend door?
12-07-2012, 12:48 AM
#25
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PS none of the t-stats were the fail safe ones, coolant level stays fairly steady with cold motor, I let it run for a bit with the cap off to see if it would burp, got a few bubbles but nothing unusual. Thanks again for all the replies
12-07-2012, 09:57 AM
#26
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I believe the temp control is cable operated and possibly can be seen from the passenger side floor board up under the dash. It controls the amount of hot air that gets blended with the cold air. Heat can be added to the cabin regardless of what position the middle vent selector **** is in. Have someone move the temp **** while u r under there with a flashlight. Presuming it is cable operated, maybe the cable has slipped or come loose.
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