Hey guys, hope you dont mind but this post is actually about my 2000 TJ that I have (4.0L), everyone is so quick to help here, and I need heat like NOW. I live in Canada and have no heat in my Jeep :-( I tried putting a garden hose to my heater core intake hose but all I got out the other end was little dribbles, how do I flush it out so I can get heat!!?? do you use chemicals or a pressure washer of some sort? Local shop wanted 100 bucks to flush it out! I think thats daylight robbery. I dont even dare call the stealership for a price quote.

 

If you're putting the garden hose through it and the other end is only letting out little dribbles you have a clog. Try running some CLR in it for 5-10 mins and then flushing it with a hose again.

 

Okay I tried the CLR and it is still clogged. I also used hot vinegar. I used a whole bottle of CLR it dribbles out the other end, all in all clr was probably in there for about half an hour. I need another solution, isnt there a way to mechanically remove the debris that has accumulated? What about a long flexible pipe brush? Can i remove the hoses at the firewall and shove a brush in there to get crap out? I really need a solution that will work, fountain tire quoted 700 bucks to replace it!!!! Anyone got a good picture of what it looks like inside? If I know the schematics of it I might be able to make something that will weasel through and clean it. Thanks anyone for help, please help, it's getting cold soon

 

I wouldn't try to run any wire through there or anything. It's essentially a smaller radiator that draws the heat from your coolant. The fins can be delicate and if you punch through something you risk getting coolant on your passenger side floorboards.

It sounds like yours is pretty thoroughly plugged. If you can't unclog it by running corrosive chems through it (try Drano, just be sure not to let any go back into the return hose) I would recommend just replacing it. It isn't that hard to do and and when you get the new one in you'll have generous heat.

In my old '87, I could pull the entire assembly down by loosening the passenger side of my dash. It would slide away from the firewall and down. Then you remove the heater core, clean the ducts and evap. cooler, and reinstall.

 

So you recommend replacing it? Can you replace it from the outside, in the engine compartment or is the inside firewall the only place you can access it from? I will try drano first, I really dont want to replace it, I don't have that much free time but I guess if you say to not put anything through the tubes then I will have no choice? You would happen to have a picture of your heater core would you?

 

I recommend replacing it simply because you know it'll be a reliable heat source and you can be sure it will last years to come. If you live in Canada, it would give you some peace of mind to have a new heater core in there rather than hoping your old one doesn't clog again. Drano WILL eat away at aluminum, so be sure to run it through and then rinse it out well afterwards.

Heater core replacement is done by unbolting it's housing assembly from the cabin-side of the firewall. There are four long screws holding it to the firewall that can only be accessed from the engine bay surrounding the bolts for the blower motor. Once the assembly is loose, it can usually be finagled downward and outward to gain access to the heater core. I've heard of people removing their entire dash but if you just loosen it enough to provide an inch or two of clearance the rear bolt studs will clear the firewall. Here's another thread showing the process
https://www.cherokeeforum.com/f2/ple...ter-core-5551/
Still, I was able to remove mine similar to the way you change the ink cartridges of a printer. It has to move back and down before it can slide down and out of it's cavity in the dash.

Furthermore, if you're putting some work into your Jeep I would install freeze plugs or an engine block heater and consider a remote start. Being able to warm your engine up before you drive it is comfortable for you and good for your engine.

 

You mentioned placing the hose into the intake side, have you tried
doing both sides, back and forth? There's a link on here somewhere
where the guy is using air pressure to help clear it. If you're going to replace
it anyways, you might as well try it. If I can find the link, I'll come back and post it
for you.

 

found it:
http://www.ericthecarguy.com/videos.aspx?vi=dcL_0TWeZJY

 

That was a great tip! Just watched the clip...good tips and laughs all in one. T/Y

 

Hey guys, thanks for the replies, I did try both ways actually, forward and back flow. in the video he uses CLR, I tried that and it didnt work. He used compressed air, I thought you werent supposed to subject your heater core to any pressure? I will try drano and a backflush and hope for the best, I really dont want to replace it.

 

Try the CLR method one more time using the video as a guide. Leave it in there a little longer this time.

If that doesn't work, you are going to have to bite the bullet and replace the heater core.

 

Where's the valve on a 2000 TJ? On my 84 one time the whole back of the butterfly was mounded with deposits, so fully open was 1/2 clear. Anyway I'd want to know it wasn't an issue with my valve. I gather the compressed air idea is a last ditch shot. Kill it or cure it.

When I use vinegar on rusted tools and stuff, I wait weeks, works great btw.

 

I was having the same problem, no heat. I took eric the car guy's advice this weekend and ran Zerex Radiator Super Flush through my heater core, I picked it up at Napa. I let it sit for about 15 minutes each time for 3 trials and then did CLR once after that. I used compressed air to blow everything out at about 100psi. The CLR and Zerex reacted in the core and the last trial blew out a bunch of foam. Rinsed it all out by letting the garden hose run through it for about 5 minutes and a final shot of compressed air to clear it. All I can say is, WOW! I have more heat than I know what to do with now. No leaks in the heater core either. Compressed air *should* be fine, and I noticed that just running the garden hose through it didn't remove any debris, it took the blast of air to get things moving. Hope this helps, goodluck!

 

It can't hurt to try all these things, worst case senario you have to replace it. That said I say put a new one in. I haven't done one on my xj so I can't give you the specifics but, I did one on my ford pick up and it's not rocket science. I think for the amount of time you are spending trying to fix the one you have you might as well just put a new one in and be done with it. Then you will know it's good to go and you won't be stuck in -20 weather with no heat.

 

I know it's not rocket science, but the heater core in my TJ is inside the firewall, gotta take the dash apart and I don't have time for that right now, I will on my days off but those arent for another couple days so, thanks everyone for the advice, I will try flushing it some more and if that doesnt work I will have to replace it on my days off. I will update on whatever solves my problem