XJ Cherokee Heat Issue. Take 4.

MrChaos wrote: In reply to Swank Force One: swap in a 98 dash plus system to fix issue?

LOL.

The 00 DOES have a 2 tone tan/black interior that i hate. I want the charcoal grey interior.

Could be fun.

Unfortunately, the idea now that i have the 98 is that the 00 will just be maintained, and not further modified. Maybe save for a subwoofer and some adjustable rear shackles to fix the angle.

MrChaos wrote: or install a MOJAVE HEATER https://www.flex-a-lite.com/mojave-heater-152.html

This brings me to another question.... will start new thread.

What is the next move? Heat goes in, but it doesn't come out. It has to be going somewhere...

Swank Force One wrote: How do i tell looking at it from the engine bay? What would be symptoms of having the wrong one? (And what sort of idiot would put the wrong one on?) I highly doubt it has the wrong one. We're the 3rd owners, and the guy we got it from wouldn't have done that.

Generally it will overheat. Remember that the return hose for the heater core goes directly into the water pump; that's why I mentioned it. I know of no way to verify the correct pump without removing it, though.

I ran this question around the shop, the consensus is to 1) check the temp with the door in the full cold and full hot positions, see if there is a temp difference. If not or if it's very small, check to make sure the various 'doors' are timed right. If it has vacuum operated doors, make sure the actuators are opening/closing correctly.

noddaz wrote: What is the next move? Heat goes in, but it doesn't come out. It has to be going somewhere...

Next move is i suppose i'm going to sack up and rip the dash out over Thanksgiving weekend, because i really didn't need a relaxing weekend after an entire year of busting my ass at work and trying to get cars ready for events.

Curmudgeon wrote:

Swank Force One wrote: How do i tell looking at it from the engine bay? What would be symptoms of having the wrong one? (And what sort of idiot would put the wrong one on?) I highly doubt it has the wrong one. We're the 3rd owners, and the guy we got it from wouldn't have done that.

Generally it will overheat. Remember that the return hose for the heater core goes directly into the water pump; that's why I mentioned it. I know of no way to verify the correct pump without removing it, though. I ran this question around the shop, the consensus is to 1) check the temp with the door in the full cold and full hot positions, see if there is a temp difference. If not or if it's very small, check to make sure the various 'doors' are timed right. If it has vacuum operated doors, make sure the actuators are opening/closing correctly.

There's a pretty good temp difference, just not as much as there should be. Goes from REALLY cold to lukewarm.

The hot/cold door is working, but may not be dialed in 100% correctly. I'm going to check that on Saturday morning before she takes it to work.

The "position" (feet, defrost, face, etc) door is working properly.

I don't have a way to tell if the fresh/cabin door is working without removing the dash.

I think after more research online, the ducting thing isn't really a possibility with how the system works.

Unfortunately, with the knowledge that the core has been replaced, i'm pretty sure i'm fighting the "XJ Aftermarket Heater Core" syndrome.

People are measuring 50F differences between aftermarket and OEM. Aftermarket seems to have about half the fins and rows as OEM.

Looks like i'm going to bend over and take it up the ass for an OEM core and then rip the dash out.

FML.

In reply to Swank Force One:

Water pump not circulating properly, not enough flow rate.

Advan046 wrote: In reply to Swank Force One: Water pump not circulating properly, not enough flow rate.

I think we hashed that out previously in the thread. Engine RPM has no bearing on heat output, so we ruled it out.

Swank Force One wrote:

Advan046 wrote: In reply to Swank Force One: Water pump not circulating properly, not enough flow rate.

I think we hashed that out previously in the thread. Engine RPM has no bearing on heat output, so we ruled it out.

I noticed that but...

Everything you have described as the issue reminds me of my 89 Cherokee heat issue. The solution was new pump needed.

Of course all that awesome restored water pressure caused old hoses to fail

Advan046 wrote:

Swank Force One wrote:

Advan046 wrote: In reply to Swank Force One: Water pump not circulating properly, not enough flow rate.

I think we hashed that out previously in the thread. Engine RPM has no bearing on heat output, so we ruled it out.

I noticed that but... Everything you have described as the issue reminds me of my 89 Cherokee heat issue. The solution was new pump needed. Of course all that awesome restored water pressure caused old hoses to fail

Is there a way to check this without taking the whole damn thing off? I think i'd rather replace a water pump than a heater core, but i'm not interested in doing both in the name of science.

I've never seen it get higher than 215 on the gauge.

It does have all new hoses, so at least if i replace the pump, they won't explode.

In reply to Swank Force One:

pump takes maybe an hour, most of it is pulling the rad. I think you can do it without pulling the rad but you get more room with it out.

MrChaos wrote: In reply to Swank Force One: pump takes maybe an hour, most of it is pulling the rad. I think you can do it without pulling the rad but you get more room with it out.

Do we think this is worth just throwing a pump at it before spending $250 and a weekend on an OEM heater core to see what happens?

Swank Force One wrote:

MrChaos wrote: In reply to Swank Force One: pump takes maybe an hour, most of it is pulling the rad. I think you can do it without pulling the rad but you get more room with it out.

Do we think this is worth just throwing a pump at it before spending $250 and a weekend on an OEM heater core to see what happens?

a new waterpump for a 4.0 is $30 and then you have to refill the radiator. and 1hr +$30 < $250 + 8hrs book time.

I have to weigh the time SWMBO spends in a cold XJ, too.

But i guess this is one of those things that just diving in on a heater core isn't a guarantee either.

Le sigh.

I hate cars.

In reply to Swank Force One:

you can do the water pump in an afternoon leaving a few days to test before you see if it is the water pump or heater core. And if it isnt the water pump, well you now have a new water pump and have narrowed the issue down the the last possible option, which happens to be hell to replace.

True story.

Not like it'll hurt to replace a 200k mile water pump anyways.

In reply to Swank Force One:

with 200k on the water pump that would be the first thing i would replace with a new part for any cooling/heating system issue...

I don't know if it has 200k on it. The truck has 200k on it, i haven't replaced the pump, but we bought it over 4 years ago at 172k miles.

The biggest risk on the water pump are the potential broken studs/bolts.

Good luck with it.

Advan046 wrote: The biggest risk on the water pump are the potential broken studs/bolts. Good luck with it.

Does it help if there's no rust on the truck at all? Or is this a cycle thing?

Also if its not had the cooling system maintained very well, expect a lot of rust/mud in the bottom of the water jacket when you pull the pump, you'll need a good garden hose to blow it out.

Water pump replaced. Still no heat.

Hoses to and from heater core are both getting hot, but heat is not coming into cabin.

Are you sure your blend doors are opening properly? Unfortunately it sounds like you are going to have to pull the dash, either the core is bad or your blend doors are stuck shut.. Sux..

I cut an access panel for the hot/cold blend door when i replaced it. Won't take me much to get back up there. That's the next step i think.