Glad that fixed yours Dan! I'm still trying to figure mine out, I have the same issue you had...mildly warm heat. I've flushed the core 3 times, both ways, with air and hot water, no change in heat temp. Am I to assume if I have good flow through the heater hoses both ways then the core is good/clear??

Engine runs 210 and air flow changes from floor to defrost to dash without issue....although it does seem to blow with less force than normal...blend door issue?? How is the cold/hot dial operated, vacuum? (99 XJ)

Anyone have any other ideas or suggestions??

 

Mine blows HOT!! Too hot almost. Once the engine warms up the whole cab will be hot within minutes. Really nice the past couple days since I've been working outside a lot!!

 

I don't know what cooling system a '94 has but even my wife concedes the heater will blow you out the door.

 

Possibly could be blend door, but i wouldnt count out the heater core just yet. did you put any kind of rust eliminator in it any of the times you flushed and how much pressure were you using. First time i flushed mine a little gunk came out but after the CLR a bunch of "liquid rust" came rushing out. Also make sure that your water supply has plenty of pressure. try temporarily taping the hose from your jeep up to the water hose to ensure maximum pressure. If that doesnt work use an air compresure.

 

I didn't use CLR but the water I flushed with was hot and it was out of a spray nozzle that fit right in the heater hose and the pressure was good, nothing but clear water came out, both ways...I also used air from my compressor too, roughly 60-80 psi...I figured if there was good flow of water going both ways through the core then it's good, right? I think I'm just doomed to pull the dash and tackle a blend door issue

 

Glad I found this. My blows warm but by no means will run anyone out of the jeep. I need to try this and see what happens. Thx

 

that sucks dude, but keep us posted on how hard it is too tear it all apart. I may just end up checking mine too.

 

My heat is HOT, but it takes FOREVER to get hot. When the Jeep gets up to temp my heat gets "Warm"... warmer than outside anyway, but it take atleast 30 minutes for the heat to get warm enough to actually warm you up. Sound like a heater core on its way out???

 

they only thing a heater core can do is plug or leak if it leaks you will smell it when you first start it up all the core is is a small radiator that heats up and a fan pushes it out opposite with the a/c just with a condensor. if its not warm it either has air in it and needs to be bleed or its plugged and just needs either a flush or flush agent. if there is air in the system your core lines are the highest in the system so it will hold all the air bubbles thus making it cold which could be a cap or just air so if you flush it and nothing happens then put a flush agent in or take core out and clean or replace

 

If you go through the extensive labor of removing the core, you'd definitely want to install a new one. The part isn't that expensive.

 

So after doing some research on the blend door I found out how the mechanism works and the typical failure point so this weekend I'm going to check into that as well as vacuum leaks. I'm still not sure if my core is functioning properly even though I have good flow but I am going to try and bleed/burp the system again just for the hell of it. I'm also thinking I might just pull the dash out of my parts Jeep...for two reasons, to see how difficult it is and to remove the entire heater box and possibly swap it into my other Jeep....I'll let you know what I find

 

Yea, I guess I should have thought about that a little more. The core can't really go bad. I've pulled heater cores out of cars before so I knew how they worked, just wasn't really thinking about it.

When I got the Jeep my coolant was a dark brown/black color and my coolant bottle and radiator were filled with mud and sand, so it's probably safe to assume my heater core is pretty clogged haha. I flushed the radiator and the head, but never did the core.

 

the core is always closed unless the heater is on

 

Yes, but if the coolant was that dirty and filled with gunk when I got it, I'm pretty sure it was never changed by the previous owner and therefore was run through the core at some point, which most likely left some buildup behind. I'll flush it this spring/summer. It's not a huge concern now, I get enough heat out of it to not freeze to death, so it can wait until warmer weather.

 

oh im sure theres crap in there