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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
Alright so as the title says I ain't got heat. So far to try to remedy this I flushed both the cooling system and the heater core separately. The heater core, when plugged into a water hose, has water flow and nothing is leaking into the passenger foot well. However I do not now or before doing all this have overheating issues.
Could this be a bad thermostat or a clog somewhere? Because the heater tubing from the thermostat is hot to the touch but the out let tube is only warm.
If any of y'all have any suggestions or ideas that would be awesome.
If the hose isn't hot, there probably isn't flow. There isn't a heater control valve on a 2000, it just freely flows in the heater core. There is a possibility that the blend door is stuck in the cold position, but if the heater hose isn't getting hot, that's most likely a plugged heater core. Try looping the heater hoses together and see if they get hot when you run the engine. If so, try blowing compressed air in the heater core. Careful though. You don't want to blow it up.
If the hose isn't hot, there probably isn't flow. There isn't a heater control valve on a 2000, it just freely flows in the heater core. There is a possibility that the blend door is stuck in the cold position, but if the heater hose isn't getting hot, that's most likely a plugged heater core. Try looping the heater hoses together and see if they get hot when you run the engine. If so, try blowing compressed air in the heater core. Careful though. You don't want to blow it up.
So even though when I flushed it with a garden hose and water came out the other tube it can still be clogged? Does coolant have a way it can bypass rows of the heater core fins then? And I'll give your suggestion a go and see how it goes.
Did you flush the hoses too? Check the "tube" coming out of the water pump for the heater core return.
I flushed the tubes but not the metal pipe going into the water pump. I did look into it a bit and it did look a bit funky, so you think maybe that pipe could be clogged?
Year: 1998 Classic (I'll get it running soon....) and 02 Grand
Model: Cherokee (XJ)
Engine: 4.0
Hmmm. Just an idea here, but I'm wondering if the flow through the heater core is the first to go when a pump impeller gets rusted away, like this one. As the rust progressivly removes material from the fins, the pump will move less and less coolant. I'm speculating that maybe the heater core needs more push to move the coolant through it, so the reduced flow from the pump might not be enough to move it through that part of the circuit.
One way to find out is to have someone add water to the radiator (get a hose in there) while you run the engine with the heater hoses disconnected. See what comes out.
Fins gone. Not moving much coolant. Just enough to fool you!
Hmmm. Just an idea here, but I'm wondering if the flow through the heater core is the first to go when a pump impeller gets rusted away, like this one. As the rust progressivly removes material from the fins, the pump will move less and less coolant. I'm speculating that maybe the heater core needs more push to move the coolant through it, so the reduced flow from the pump might not be enough to move it through that part of the circuit.
One way to find out is to have someone add water to the radiator (get a hose in there) while you run the engine with the heater hoses disconnected. See what comes out.
Fins gone. Not moving much coolant. Just enough to fool you!
Hmm you raise a valid point. And a high possibility as well, considering I'm finding a lot of old Daimler Chrysler plastic and such. Honestly I'm close to just doing a cooling system overhaul at this point.
You flushed the heater core in both directions, right?
No not in both directions, I just thought if it's flowing fine in one direction it should have been fine in reverse. I assume I'm wrong about that then?
Flush the core in BOTH directions. Do NOT use high pressure from the hose. Just a trickle and don't plug the core or impede the water flow. The cores are EASY to pop with household water pressure.
On my '99 I tried flushing several times. As a very last-ditch try, you can carefully dump some CLR cleaner in the core via the hoses and let sit for NO MORE than 3 minutes. Flush WELL with water. Repeat one more time. This is a LAST DITCH EFFORT tho. IF your core is shot/bad, using CLR will either work or make it leak. In which case you know what needs to be done....
Been there.. Done that. Great way to eat up a Saturday replacing a core in a 97+.. Take your time.
Oh I missed the part where you said separately. Yeah if you flushed it out, it should be flowing coolant.
I don't think the XJ ever got a plastic impeller water pump, but I've definitely seen them look like the above picture more than once.
That's okay lol. The cooling system was flushed twice then filled and the air was burped out. The reason I did all that was because the old rad cap seal went bad and had a ton of gunk stuck to it and in the overflow tank as well, and I'm sure in the rest of the system. I can only imagine I am still dealing with that issue too. I don't have any idea how old the pump or thermostat is, nor how old all the coolant/heater lines are.
Flush the core in BOTH directions. Do NOT use high pressure from the hose. Just a trickle and don't plug the core or impede the water flow. The cores are EASY to pop with household water pressure.
On my '99 I tried flushing several times. As a very last-ditch try, you can carefully dump some CLR cleaner in the core via the hoses and let sit for NO MORE than 3 minutes. Flush WELL with water. Repeat one more time. This is a LAST DITCH EFFORT tho. IF your core is shot/bad, using CLR will either work or make it leak. In which case you know what needs to be done....
Been there.. Done that. Great way to eat up a Saturday replacing a core in a 97+.. Take your time.
Okay that's definitely some good info. What's the best way to flush water through it if not with a hose?
You can use the hose, but just turn it on a little bit. Wide open will cause bad things to happen.
Also.. WHEEEEEE!
Oh yeah that's basically what I did. And oof yeah no I wanna try to avoid having to replace the heater core because I'm definitely not experienced enough to do it myself.
10-09-2021, 04:43 PM
2000 Cherokee sport 4.0 no heat
