Is my radiator cooling too much?

[Digger87xj]

4-8 hours soak should do it. If it is real cold go for the overnight or 8 hours. The damper door, if it is the same as older jeeps, is near the passenger side door and dash corner, under the dash at the bottom. It is about 4"x4" and very obvious looking. Even more obvious when it moves for selection changes from max A/C to vent! On mine I can see the blower wheel when it opens.

That is the recirculation door. outside vs inside air.

The blend door is the one that controls temperature.

Mode doors control airflow floor/vent/defrost.

The blend door on 2000 xjs are controled by electric motor, and are also prone to breakage due to the force of said motor. It is obvious when it is broken as you can hear it flop and a quick temp change when the blower is put on high.

I recently replaced a heater core in an XJ where someone used stopleak (I call it stopheat) in the system to try to fix a leaky radiator. All it did was clog the heater core and was un-flushable.

 

[scottmcneal]

I recently replaced a heater core in an XJ where someone used stopleak (I call it stopheat) in the system to try to fix a leaky radiator. All it did was clog the heater core and was un-flushable.

This is why i use Black pepper. Yep the stuff you cook with.It will stop the leak and NOT plug the cooling system or heater core.

Just let the shop know when you take it in.

 

[Ecomike]

This is why i use Black pepper. Yep the stuff you cook with.It will stop the leak and NOT plug the cooling system or heater core.

Just let the shop know when you take it in.

That is a very old race car trick, circa 1930s. It works, but it is the fiber in the pepper that does the trick, the same kind of plant fiber used in Bar's leaks pellets.

Most cooling system disasters are caused by idiots using tap water or people letting the antifreeze get too old or exhaust leaks into the coolant, or a combination there of. Tap water is often loaded with calcium that reacts with the silicates to form concrete scale. CO2 from the exhaust forms carbonic acid, lowers the pH and drops the silicates out of solution forming white sand/concrete like scale. And age drops the pH over time. Factories have added the plant fiber pellets to new car radiators since before WWII for warranty reasons.

 

[OntheOffRoad]

Clogged heater cores seem to be common in Cherokees. (from the one's I've owned and come across).
No need to take them to a shop to have them flushed. It's easy.
Your core will not get properly flushed using a normal flush fill kit. If its clogged the flow will just go elsewhere and not thru the heater core.
To flush only the core, try this.

Disconnect both the lines to the heater core at the water pump and thermostat (easier to get at the connections at the front of the engine and it gives you a couple feet of hose to work with).
Take your garden hose, no nozzle connected just the end of the hose and turn it on medium flow.
Wear clothes you don't mind getting wet, and do this in an area that has plenty of space/drainage.
Hold one hose over the edge or the car (having a friend around helps) this will be the outlet. Using both hands, push the garden hose against the other heater hose and seal it with the other hand. Water will spray from your hands, don't worry about it.
The water pressure from the hose will flush the core. Hold it for a few seconds, then pull the hose away and repeat several times. This on/off cylce causes air to get in and helps the flushing process as does the surges of water when you do this on/off thing.
You will get 'bursts' of nasty stuff that flow from the heater core.
Now, reverse the flow by flowing water into the other heater hose.
Keep doing this until no more nasty stuff comes out of the core. It take me about 15 minutes to do this. (20 or more gallons of water). You can turn the hose flow up after the flow thru the core is decent. If you start with too much flow from the hose too quickly it just sprays you down more.

You should notice a considerable increase in the flow thru the core when finished, in comparison to the flow when you started.

Note if you have a valve in you heater lines, it will need to be open for this process. I use a zip tie to hold it open. Or best is to remove it and go directly to the heater core with your hose. But this makes a bigger mess and can drown the inside of you vehicle.

I did this in Colorado after commuting over the moutains in winter w/o heat for a few weeks. Had to wear a jacket and snow shoes inside the car on the way to Telluride every day.
Flushed it and it was all warm and toasty from then on.
Good luck and let the heat flow!

 

[2X_01_Jeeps]

Flush process is good as written.
I've used hose connectors to the garden hose which makes less spray.

My best enhancement is that I had to do this for my euro-sedan when the outside air temp was in the 30s.

I ran my garden hose to the hot water faucet in the laundry room so I could flush with HOT water ))))

Also made sure to add a discharge hose from the outlet side into a bucket so I could catch what was blocking and could keep from spraying much.