XJ-kee

Hey all. I've worked through just about every problem my cherokee has had over the last 5 years. Right now, I'm about to drive it into the lake across the street and be done with it.

I have absolutely no heat in the car what so ever. And I'm at that point with dealing it where I want to sit down and yank at my hair, laughing maniacally why I stare into the front grill.

A little background on previous relevant fixes: About 3 years ago I replaced a bad radiator, therefore drained, replaced, and burped the coolant system. I've replaced my thermostat 3 times for various issues - none of which meaning they were bad, but they're cheap and I had the water pump off so I just replaced the thermostat as well.

Last year, the 0331 head crack paid me a visit. My dad and I tore down the whole jeep and while I had the opportunity, I replaced a boatload of things. Included in which was another new thermostat, water pump, upper and lower radiator hoses, and everything attached to the water pump. My dad taught me everything I know about cars, and he and I filled and bled the system entirely. However, I have no heat anymore. I live in michigan. It's cold in the winter and I have an hour drive to work. I even went so far as to buy one of those spill-less funnels, park the jeep on an incline, and then bled the system hoping to get any bubbles to plop out of the block.

Relevant information:
- Jeep never goes above halfway between 210 degrees and the line before it (~195 degrees then), which makes sense because I have the 195 degree thermostat.
- Upper hose on the thermostat is piping hot (going to/from the heater core)
- lower hose (coming/going from the heater core) on the thermostat is cold (seems like this should be at least warm, possible blockage in the heater core?)
- Upper radiator hose is piping hot, however when I squeeze it, air continually bubbles out of my funnel. Today, I spent about 30 minutes squeezing and releasing this hose, bubbles popping every time.
- There are no bubbles in the overflow tank or in the funnel if I let the system idle and do nothing to the hoses
- Oil still looks fine, not like I have another cracked head or something.

Questions:
- If the upper radiator hose is full, when I squeeze it should it be more firm?
- Does air still bubble out of a squeezed upper radiator hose in a system that is functioning correctly?
- how hot should the "lower" hose on the thermostat be?

Tomorrow I will attempt to pull the hoses off of the heater core and blow it out with water to get the blockages out.

chipmaker

Sounds like a blocked heater core to me. Both heater hoses should be around the same temp. Take the hoses off and use a garden hose to back flush it. I had the same problem a while ago, sadly it was a precursor to a failing heater core. Also the best way to "burp" the system is to fill the radiator all the way up with the engine running and the heat on, put the cap on, fill the overflow tank and let it do it's thing. As long as your radiator cap is good the system should purge itself after a few warm up and cool down cycles.
Just keep an eye on the level in the overflow tank.

XJ-kee

Thanks for the info. Which way do I connect the hose for sure? I believe it's hose on the top connection, water bleeds out the bottom one?

I saw some guy had a special connection for that flush, are these necessary or just a ...convenience thing?

chipmaker

The supply line should be the lower hose at the firewall. Just remove both heater hoses from the engine, route the lower one down so it will dump underneath the Jeep and use a garden hose to force water through the top hose.
The special connector is for doing a whole system flush. After you clear the blockage would be a good time to do a full flush. You can pick up a flush kit almost anywhere for like $5, just follow the instructions on the package.

nujeepguy

i flushed my 97 both hoses were hot! but not much heat, i was careful not to use full garden hose pressure , might damage the core.. i went back and forth reversing the flow thru the core. im convinced it plugs up close to the hoses and we never get the whole thing clean.
later i had 2 hot hoses but not much heat.
also you gotta be sure your heat control cable is not malfunctioning like mine was. i had to reach under and help it.
still not much heat. the cable end bent instead of moving the valve/whatever.
i think it takes a new core. jmo
my 2000 right now has good but not super hot heat.