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Philprof
April 5th, 2008, 10:25
I have a 2000 xj with a coolant leak. I've searched the threads for similar issues, but have only found help eliminating a few possibilities.

Story: I had the head replaced a few months ago (cracked during and overheat). the thermostat was replaced as well. The coolant would leak after running for a period of time (45 mins or more), but only after it was turned off. It would escape from the overflow neck of the bottle, and from a small 4 inch curved hose at the base of the firewall (passenger side). after replacing the radiator cap (16 psi), it only leaks from that small hose.

Also, it usually runs around 210 degrees. I was in Big Bear the other day and the radiator seemed to be working hard for a 50 degree day (at over 210 degrees, call it 220-225). There aren't more than a few mods on this cherokee either.

thinking about a csf 3 core. thoughts?

Mudderoy
April 5th, 2008, 10:59
I thought the small hose on the firewall was part of the A/C system...

I overheated my 1998 XJ some years ago. The shop said the head was warped so they sent it out to be milled.

The culprit for the overhead was the POS OEM water pump with factory plastic fins.

Anyway all was good for a month or so and then I got a leak. It was leaking from the radiator around the end cap. I had it checked at a radiator shop and they said the "PLASTIC" end cap was not repairable, so the radiator needed be be replaced. I replaced it with a NON-PLASTIC radiator.

Now years later and a couple of minor over heats, I have replaced the thermostat with a 180 degree HIGH FLOW thermostat. I will be replacing the mecanical fan with an electric, plus I will be replacing the 2 core radiator with a 3 core. The next time I replace the water pump (on my 4th one) I will use a high flow water pump.

The XJ over heat is the biggest problem I have had with the XJ, and I consider it designed poorly, but I'm going to fix that.

Philprof
April 5th, 2008, 11:44
You know, i think you're right about the small hose. it leaks after i shut it down even if i haven't used the A/C. Would this be normal? I'll check the next time it happens to see if its pure water or coolant...

CharlesS
April 6th, 2008, 06:24
Several years ago while attending a NAXJA event in Moab; I found a small puddle of coolant under the Jeep after the temperature at night dropped into the low 40s.
I did a search in the engine compartment and found coolant seeping thru where the plastic tank is attached to the aluminum core. This was the factory heavy duty 2 core.
Over the next couple months I purchased a 3 core radiator, upper and lower hoses, heater hoses, thermostat, and a thermostatic clutch. Ran this setup for about 2 years and found that while the 3 core has more surface area; the tubes are small and prone to trapping the small iron nodules that can break free from inside the engine.
Recently purchased a Modine HD 2 core, had the system power flushed at Goodyear and then installed an inline strainer on the radiator return hose. This will trap any nodules and ensure the radiator tubes wont get plugged.

Saudade
April 6th, 2008, 07:59
I thought the small hose on the firewall was part of the A/C system...

That would be the heater core.

When the head was removed, they probably pulled the hoses going to the heater core. It may only need a little tightening. I would remove and carefully check the end to make sure it's clean and the hose end is not cracked.

poorboy_616
April 6th, 2008, 08:25
Just another reason why I love the closed system with the pressure bottle...

Constant 190, loaded or not....

It is the same basic system that Tractor-trailer rigs use....

I can run it three quarts low, and it doesn't notice....

Also, most of the problems people have with the Renix are cooling systems are due to improper bleeding.....

Philprof
April 8th, 2008, 15:13
bump

Shorty
April 8th, 2008, 16:49
bump

bump?? you were checking the leak and letting us know---

was it H2O or coolant? I'm going out on a limb here, but if it's coming from the little hose on the firewall when you're not using AC-- your heater core is leaking into the HVAC system and draining the coolant there. Try running the defrost on high heat for about 20min and clean the inside of the windshield-- I'll bet there's some coolant residue on it.

Philprof
April 8th, 2008, 16:54
bump?? you were checking the leak and letting us know---

was it H2O or coolant? I'm going out on a limb here, but if it's coming from the little hose on the firewall when you're not using AC-- your heater core is leaking into the HVAC system and draining the coolant there. Try running the defrost on high heat for about 20min and clean the inside of the windshield-- I'll bet there's some coolant residue on it.

My bad :doh:. It appears to be water. though your later comments make me wonder about the infrequent smell of coolant throught the air system (no a/c on)...thanks for the reply