3HUNNED

I recently purchased a 2000 Jeep Cherokee Classic w/ 192,xxx miles.

i went under the hood to check the coolant and everything and there was sludge and brown, almost sand like stuff inside the filler cap junction in the radiator and on the radiator cap.



i did a full flush of the system and put in a new thermostat and tstat housing.

it hasn't overheated since but im still not getting any heat through the vents.

im wondering if maybe the heater core is clogged? or any possible reason why i still have no heat!
thanks guys!

klees

yeah check your heater core and see if its clogged or not

Throttle Jockey

could also be heater control valve not opening. you need to make sure the antifreeze is getting to and through the core.

RICZR2

I'd flush the heater core first...easy and cheap to do.

3HUNNED

yeah i was told by a buddy that some part stores sell this 2 part cleaning solution for the cooling system. im hoping that will clean out the heater core and everything else.

another thing i noticed is that the position selector for the HVAC system only blows throught the defrosters even when i change the position on the switch. I dont know if thats a common problem with the Jeeps?

sbslinde

Defroster only is a vacuum issue. Check for a cracked or disconnected vacuum line. Mine was disconnected at the firewall near the heater hose inlets. Hope you can get the heater core flushed. Changing it in my 2000 was a pain.

Jeff

Desert Rat

Brown sludge? That would concern me, thats ussualy a sign of a blown head gasket (oil mixing with coolant), Has the head gasket been replaced recently?

Handycapt

FLUSH THE HEATER CORE! XJ's are notorious for clogging heater cores. You don't need any special parts to flush it though. Just disconnect the heater hoses from the outlet, and push your garden hose up to the lower hose. You can hold it by hand easily enough to seal it off. This will back flush your system. Then switch and hold the garden hose against the upper hose. Do it a couple of times, and reconnect your hoses and clamps.

Takes about 30 min and all you need is a garden hose with water, and a pair of pliers (I'd suggest vice grips though) to move the hose clamps.

It may be some other things though. What does your temp gauge say? Does it run at normal temps? After your jeep is warmed up, put your hand on the upper heater hose (be careful, it's supposed to be hot). Is it warm? If not is the upper radiator hose warm?

May just be that you have a air bubble stuck in the system. Is the heat non-existent? Or is it intermittent?

3HUNNED

i recently got the car and i don't have any idea what was done on it. i have a feeling the car was neglected too. I got it with a 192,xxx miles on it as well, so who knows what was done (or not done lol).

actually, when i picked it up, it was blowing some warm air out. but after i flushed it, it just blows cold so im thinking i moved some gunk around in there and probably clogged the heater core.

are the switches controlled by vacuum? i had no idea

3HUNNED

So I did what you guys said to unclog the heater core and now I have flow but there's water on the floor of the passenger side. I had it running forba good hour after and I pulled the carpet back and didn't see any water dripping or trickling. I also noticed when I rev up the engine the air gets warmer or "hotter"

Handycapt

that most likely means that you need to add more antifreeze. Is your reservoir full? It should be at the hot mark when your car is quite warm. If it's not you need to add more. If you don't have enough in there then it won't flow into the heater because the hoses for the heater are at the top of the block. Fill your overflow when your car is cold, and then run it for bit and check to see if it has pulled the antifreeze in. Your jeep should take ~2.5 gallons of antifreeze. If there isn't enough in there then you will start to get air bubbles. Don't fill it through the radiator cap, just put it in the overflow. It will get sucked in. When your car is cold it will suck the antifreeze back in as well. So run it then shut it off and come back and check it in a bit. If the overflow is empty, add more.

The water on the passenger side floor isn't a good sign though. Your heater core is probably cracked. There aren't any other ways for the water to get in, unless you have really bad, loose fittings in the firewall where the heater hoses go inside.

You won't see any dripping unless you have enough water inside the cooling system to flow up and into the heater core. Make sure it is full and pull back the carpet and check again.

Oh and check your inbox...

Bills2000

Hey everyone
New to the forums and wanted to say thanks for some valuable information. I too have a clogged heater core and the advice is encouraging since you have to pull the dash to replace the heater core.
was not looking forward to the bill or the project.

Bills2000