97+ heater problems

[selarep]

I'm having some trouble on my 98 with the heater. It blows luke-warm air and I just did a coolant flush. I also ran air through the heater core. I turn the heater on full blast and i'm still cold! What could it be? There's no heater controll valve so thats out of the question...

 

[Durango-Bob]

Are you running the stock engine thermostat? You should be, a colder one will cause your problem and not be good for the engine, either. When running, you should see your engine temp hit around 210.

 

[selarep]

I'm using a stock 195* t-stat. I was using a 180 before and my temp never hits anyhitng above 210, always below.

 

[jmowens]

Sorry for your troubles, but why, oh why, in the world are you running your heater?!?

 

[selarep]

Sorry for your troubles, but why, oh why, in the world are you running your heater?!?

wtf? because... it gets cold.

 

[TacticalFats]

Blend door?

 

[Blaine B.]

Yea, totally, it's getting a bit chilly this time a year.

But you ran air through the core? My guess is there's a big air bubble in there or something.

 

[selarep]

Hmm... It is the same temp as it was before I did the flush, freakin cold. Especially this morning coming back from camping, it was 40* last night!!! What the heckis Blend Door?

 

[selarep]

update:
Hooked up the heater core hoses to a water hose and turned it on blast (35psi of water) and a little muddy water came out. Then Hooked up compressed air (160psi) to the inlet fitting and BOOM out came mud. And LOTS of it. Looks like the PO put that copper head gasket sealant in it and it clogged the lines in the heater core. Flushed it from both the inlet and outlet of the heater core with water and air untill clear. Now i have HOT air.

arty:

 

[comanche91]

I'm having some trouble on my 98 with the heater. It blows luke-warm air and I just did a coolant flush. I also ran air through the heater core. I turn the heater on full blast and i'm still cold! What could it be? There's no heater controll valve so thats out of the question...

Yeah, I've read that 1997+ XJs had no vacuum water control valve as in earlier models. So then what "turns on" the hot water flow to the heater core? This would be a good mod if feasible to lose the troublesome water control valve.

 

[selarep]

Yeah, I've read that 1997+ XJs had no vacuum water control valve as in earlier models. So then what "turns on" the hot water flow to the heater core? This would be a good mod if feasible to lose the troublesome water control valve.

Nothing turns on the flow, its always flowing through the heater core. The thing that activates the heat is the door to the heater core that is opened when you select heat on the controls. Its cable operated (on my 97 that is) so the knob opens a door and air is pushed through the core into the cab.

 

[BIGSLVRXJ]

Yeah, I've read that 1997+ XJs had no vacuum water control valve as in earlier models. So then what "turns on" the hot water flow to the heater core? This would be a good mod if feasible to lose the troublesome water control valve.

Just ditch the valve, it's really not necessary (sp?). I did it to all my older 4.0s and had no trouble.

 

[darjevon]

Just ditch the valve, it's really not necessary (sp?). I did it to all my older 4.0s and had no trouble.

easy way to remember spelling of NeCeSSary?
one Carthorse has two Sugars.

fixing lukewarm heater?
ditch the heater valve. Could also be vacuum issues with one of the solenoids on the box, possibly a broken or sticking linkage arm. Removing the box is a really nasty job.

 

[cykaaro]

having issues with my heating. had the whole cooling system thoroughly flushed, which it needed. Basically, I've a '90XJ. Heat is pretty much luke warm, but seems I can at times get it to come out hot like it should occasionally. Really wondering if this valve is the issue? So, if I remove it, then what hose needs to be connected to what? I really need my heat working as it's getting quite chilly out [4*C].
TIA

 

[selarep]

having issues with my heating. had the whole cooling system thoroughly flushed, which it needed. Basically, I've a '90XJ. Heat is pretty much luke warm, but seems I can at times get it to come out hot like it should occasionally. Really wondering if this valve is the issue? So, if I remove it, then what hose needs to be connected to what? I really need my heat working as it's getting quite chilly out [4*C].
TIA

http://www.naxja.org/forum/showthread.php?t=75519&highlight=heater+valve
There's your answers. If you have any more problems its best to post a new thread.

 

[BIGSLVRXJ]

http://www.naxja.org/forum/showthread.php?t=75519&highlight=heater+valve
There's your answers. If you have any more problems its best to post a new thread.

Hey cool that's my thread. Basically though if you want to bypass it you'll need to connect the hose that runs from the water pump pipe to the lower heater core tube and the hose that runs from the T-stat housing to the upper heater core tube like so...

Of course on your 90 with the closed system it will be slightly different, you will have to replace the T's in the system with other ones (I would recommend brass) since you have to go up and over to the coolant bottle.

 

[Blaine B.]

What thermostat are you guys with the problems running?

Stant + dealership OEM are the best I've used. I'm using a dealership thermostat now. My heat was too cool with autozone crap thermostats.

 

[selarep]

I was running a 180 at 1st but then i swapped to a 195 and that wasnt even my problem, it was my heater core. damn crap.

 

[cykaaro]

From everything I've read/heard/know always go with a 195 t-stat.

As for my heat issue, did some testing. The line into the heating core is hot like it should be, the line coming out isn't. The control valve seems to work like it should as well from what I can tell. So if flushing the core by itself doesn't work, may mean I'll have to replace it, which I hope I won't have to