Hey all! I was hoping I could get a little help here. I'm a GM guy, but my girlfriend has a 2000 Jeep Cherokee Limited with the straight six. She has about 150,000 miles on it.

First, let me comment on how impressed I am by these Jeeps. This thing still looks sweet after a bath and runs like a fine watch. It has a knocking upon startup, but if that is piston slap, it could go forver like that. It uses about a quart of oil between changes.

Anyway, she has no A/C and very little heat. According to the shop, she needs an evaporator core and they say it is a 12 man-hour job due to tearing out the dash panel to get to it. Well over $500 to change it.

She says she can live without the A/C, but here in Michigan, she'd like some heat. Will a bad evap core cause no heat? My first thought was the thermostat but the Jeep runs at 210 or slightly above after warming up.

She has overheated in the past. It was a while ago. The other night, it was our first very, very cold evening. She started the Jeep, drove away and, about two miles away, noticed steam coming from under the hood. She got some antifreeze and filled the overflow.

I checked the radiator and it is topped off, and now the overflow bottle is too full. I told her it will be purging out the overflow vent so expect some more spillage and keep an eye on the guage.

So for some reason there was steam that night. Maybe a fluke. It runs over 210. She has no/little heat. She needs an Evap core.

If you were to try fixin it to get her some heat, where would you start? I'm thinking a thermostat anyway, plus a flush to get some new stuff in there.

Any help is appreciated even if I gotta buy you lunch or something? Thanks in advance! I realize I'm not a regular here. My only real worth to offer back is a discount on a GM vehicle LOL!

 

<---- Smelling arm pits...

 

how long has it been without heat??? i would try to remove both the little hoses going to the heater core and run some water through them...see what comes out...if you have limited flow...you may need to replace the heater core...which you can kill 2 birds at once...

 

I would start with flushing the cooling system and heater core out really good. You may end up finding that your heater hose switch is bad, plugged or leaking. They are notorious for that. I would do those two things before I'd even mess with the T-stat.

 

Ok, here's what I did.

I pulled the two heater core hoses then made a makeshift attachment using pool filter adapters, a washing machine water hose, a garden hose, and lots of electrical tape. I stuck it all together on the inlet hose and had my girlfriend turn the hose on. Would you believ it worked??? I got a little flow out the outlet hose. Then I had her turn the hose on higher and... it all exploded in my face and shorted out my drop light

I put it allll back together only BETTER this time, changed the bulb, and hooked to the outlet hose. This time I had much better flow going through the core backwards.

I let it run a while like that. Then I put it all back together, topped it off with the Prestone and took it for a drive.

NO HEAT. None. The temp guage rested on 210 the whole time. My GF says it has ran at 210 since the day she bought it years ago even in the Summer.

When I got home, I felt the core inlet/outlet hoses. Inlet: HOTT! Outlet: COOL. No way was there any coolant running through that outlet hose.

Note the coolant looked like mudwater. Brown and thick.

Can there be enough sediment in the core to block the inlet channels but still flow backwards? That is what it seems to do. I was tempted to switch the hoses and see what happened.

I will also look into the heater hose switch.

 

in a 2000 im pretty sure that was the year that they went to the G05 coolant. If you mix it with anyother color it will turn into chocolate milk! Another thing would be there could be an air pocket in the heater core not letting coolant through. I would get some flush and get that old crap outa there!

 

Neglected cooling systems are death to these 4.0 motors. I've had a service advisor confirm that they get dirty and mud up quickly. When I first bought my 2000 the overflow bottle had a couple of inches of a mud like substance sitting in the bottom of it. I've flushed the system twice in a year since, and I'll probably flush it again this Spring. Start out with a heavy duty flush. Also, to me, the waterpump and thermostat are maintenance items and should be changed with your next flush if you don't know the maintenance history of the Jeep. I changed mine at 80k miles. It's also a good time to check the radiator and heater hoses.