Ok, my '92 has very poor heat output and I am getting tired of freezing and having the windshield only thaw half way up when driving in the snow.

I replaced the waterpump, heater valve, all hoses, thermostat (195*), and completely flushed the system a few months ago. My temps hover around 190-205 on the guage. Anyway... The heater is blowing strong but there is only warm air. On my '99 it will almost burn your hand from the temp of the air! I am thinking that my heater core is probably messed up as the original coolant when I bought it was like dark gravy (nasty). Spent 2 weeks and 12 bottles of Heavy Duty flush to get it to clean up. Even replaced the rad since it started leaking after the flushing. Saw that one coming..

When I flush the heater core, I get nice clear water. Both heater hoses are hot so I think that the core is not extracting all the heat due to being "insulated" by rust in the core. What are the chances that CLR cleaner would give me leaks? Should I just use white vinegar to clean it overnight? Any experiences with either?

I plan on replacing the core eventually as it's only $40 from everywhere I called but nobody has it in stock. And my R12 A/C still works too. Really REALLY hate to exacuate it since I will need to convert to 134a after that.

Any comments or ideas before I run to the store and pick up some CLR or Limeway?

Bonus pic of a new XJ heater core:

 

be easy wit pressure

 

i've never heard of using it, i'd be scared it would eat away at whats left of the heater core. and that $40 part is a huge pain when you wanna replcae it. they make heater core flusing chemicals, and between that and pressure from a garden hose is really all you need.

 

Alrighty.. 3/4 gallon of generic Wal-Mart white vinegar and my XJ smells like giant dill-pickle. I have hot running water in the garage so I flushed with that first then blew into the lines. Got some rusty water out that way. Flushed with vinegar once and then hot water.. Letting it soak with more vinegar for a few hours.. My dogs nose is going crazy on my pants.. hahahah.

I also really enjoy the way the drain is facing on my new radiator.. The nipple faces towards the rear. I made a handy extension tube from other Jeep parts that I can weasel back there and run into my containers. Sucks..



Bonus! Large dill pickle found!

 

I hear the older xj cores are easier to remove than the newer xj's.

You aren't alone in the lack of heat department. I had to endure a few months of NO heat. It wasn't fun.

This is how i drove to work with no heat:

 

on the older xj's it was a pain i think, i know the evaporator is harder than the newer ones, or grand cherokee's.

 

Success!! After using 1 gallon of white vinegar I was still getting rusty water when blowing air. Soooo... Tossed a bottle of "CLR" in there a few times and rinsed and blew it out till clear. Hooked everything back up, filled and burped and I HAVE HEAT! Lots of heat! Too hot heat..

 

were your pouring the vinegar into the upper heater hose and letting it fill the core? or using it to wash out the fins?

thanks ahead of time.

 

I was pouring the vinegar into the heater hoses (core ) and letting sit for a few then purging with hot water then blowing out the crud.

 

Thanks much diskman. Ill have to try that myself. Along with a major flush throughout to go along with the core.

 

i need to do that with mine too this summer. little heat coming out too.

 

might be a stupid question, but where exactly are you putting the vinegar into and then flushing it out? Is it where the hoses go through the firewall into the car and heater core?
And one more general question: does using distilled water in your system really matter?

 

distilled water doesn't have the minerals that tap water has in it.

 

Yeah but does it make a difference that is enough to be worried about?

 

Whats LCR?