I have a coolant leak on my 96 XJ- not a horrible one, it goes from the full mark in the reservoir to the add mark in about a 2 week span. It starts leaking after being shut off and leaks more in the bitterly cold (single digit temps or lower). Here's what I've done with it in the past year:
1. New Stant thermostat
2. New Gates water pump
3. Cooling system flush

What I've inspected:
1. WP/thermostat areas
2. checked hoses and clamp tightness
3. Took reservoir out and checked it for cracks/splits, found nothing

The radiator cap looks factory, could that be causing extra high pressure and making it leak after shut down? The XJ also still has that paper/fiber mat under the engine bay and the coolant dots seem to be in a fairly straight line across. Will investigate that further tomorrow, but just wanted to get other things to check out. Not all that familiar with the XJs. Thanks!

 

Time for a pressure test

 

Could be the heater control valve. Mine leaked mostly when the heat was on, and when the Jeep was shut off with the heat on it would really **** a lot of coolant.

Check that first by running the Jeep with the heat on and watching for the drip. Mine did it randomly at first and then very predictably. Part is like $12 from RockAuto.

 

The heater control valve is definitely wet, so I'll start there. Didn't know to check that, thanks. What's the best brand to get?

 

Not sure which brand is best because I just got what was available. I did price a Mopar brand from dealer for about $50, which is supposed to last longer (supposedly the cheaper ones don't last long). But who knows. You can bypass it if you want. Just do a google search for jeep cherokee heater control valve bypass and many threads will come up. I just replaced mine, and will carry a cheap spare in the case I need it.

Still I would check for other leaks too. Look at the engine oil for signs of coolant leaking into the oil (creamy, brownish oil). Also get a new radiator cap just because they wear down over time. Same thing for the radiator, but that's another story.

Good luck.

 

I've researched most of the by pass threads...is that the better way to go?

 

Been without one for about 3yrs after mine self destructed. Still got plenty of heat and a cold a/c. I believe MOPAR did away with that valve after '97.

 

I fixed a similar slow leak in my old Ranger with some alumaseal (the liquid kind - apparently the pellets can cause clogs and make your engine go bye-bye).

I wouldn't start off with it, since a real repair is always better, but after checking and rechecking everything, new parts and a ton of time spent on it, I gave in and it worked just fine.

 

Had something similar. Reservoir always low but no obvious signs of leakage.
First thought, the 331 head! But no signs of coolant in the oil
Finally had it pressure tested which revealed a small leak in the radiator.

As someone mentioned above, get it pressure tested.

 

I'm a bit unclear....most how to's say run the 5/8" hose to the other 5/8" nipple and ditto for the 3/4" hose. This video shows that you "mix" them (3/4" on one end, 5/8" on the other).

Which is right? Also, you need to purge the cooling system after, right?

 

Ran mine 5/8 to 5/8 and 3/4 to 3/4.

 

Ok, sounds good. That vid said that with the 97 hoses both the fire wall nipples are 3/4". So do I need to change the end of one of the hoses (if I go with the 97 style hoses?)

 

Why go with '97 style hoses? What size water pump inlet tube did you get for your new pump?

 

Thought I'd go with the 97 ones since they didn't have the heater control valve and would look neater than generic heater hose. Not sure what the pump inlet tube size is, I'd assume it's whatever a 96 WP should have. Don't have access to the Jeep till later today. Thanks for the help.

 

Edit: got the hose questions figured out. How do I ensure the blend door is working correctly/sealing right?