Bypass the heatercore.

 

Poconogeorge, please let us know if you solve this. I have the same problem. I flushed the heater core. It had no problem, clean. I can hear the heater door moving.

I have ran the jeep with the radiator cap off and I get the result one of the other posts said, it just dribbles over the lip of the opening. It seems like I should be able to see the thermostat open and the coolent rush through.

The engine, thermostat and water pump are new.

I am wondering about that little plastic diafram looking thing in your picture with the vacuum hoses attached to it. Is the a heater cotrol valve on these newer xj's like the older ones? Mine is a 97.

 

Newer xj's do not have those heater valves.2000-01.

 

Ya I saw his pic just now, no valve. I would flush the hell out of that thing and find out why the system is not moving.

 

Check the actuator under the passenger side front dash.
It controls the heater doors....and will not change between hot & cold if flawed.

 

I can move the dial and see that wire move the lever.It sounds and looks like the door is moving fine.

 

does one of the tubes going to the heater core get kinda warm and the other stay kinda cold?

 

The top heater hose is hot. The bottom one seems not quite as hot. But like I said before I flushed the heater core and it was free flowing and clean.

 

I have not solved it yet. Same as it was before. It has to be simple but I just can't figure it out yet. I work 12 hr days and don't have a garage or private yard to work in.

 

I had a lot of the same symptoms that you describe in my 00 Sport. Top heater core hose would get hot, bottom one would be warm. I flushed the heater core and changed the tstat, but it didn't make a difference. This fall I broke down and had the heater core replace, and the heat is working like a champ again.

I lived without heat last winter, but now that my daughter is driving it, it was time to fix it.

Sean

 

reverse flush with oven cleaner and then hose!

 

my friends 00 was doing the same stuff last week.. he swapped the lines and after a couple days it was better.. By swapping i mean he took them both off at the firewall and changed them left to right. I'm guessing that after awhile the scale back flushed itself?

 

Any one else...Is this OK to do? I too am experience low heat output. I have flushed, backfllushed, changed T-Stat, and new fluid. I live in Northern Minnesota and it's cold!!

 

Well I finally think I have it fixed. I thought I had it fixed last weekend after replaceing the 160 Degree thermo with the 195 and spending a lot of time burping it just to make sure.

After my son drove it over the week he said slight heat but not real heat.

So I bought more anti freeze and some CLR. I did the routine shown on Youtube. I didn't really expect it to make any difference since I had already flushed the heater core weeks back with the garden hose and the core was totally clean and flowed no problem.

I was shocked at the crap that came out of that core back flushing it with the air. I did that many times and then put in the CLR for a half hour. I then continued to flush and get more crap out. I flushed until nothing came out.

Refilled the radiator and overflow.

It is putting out real heat now.

 

Do you have a link/web address for the Youtube video? I too think this is my problem.