My last two drives (20 minutes long each) have finished with my 2000 XJ in the garage, and coolant spilling out of the passenger side undercarriage (about 1/2 gallon each time). I haven't climbed under there to look, but from the top side under the hood, I don't see anything visibly leaking. Before I start digging in, who has a guess as to what my issue is?

 

1 any coolant on the passenger side floor/carpet?

2 after/during one of your drives use a flashlight and look low on the passenger side firewall and see if coolant is coming out of the HVAC box drain

 

More than likely, coolant is bubbling out through your overflow reservoir, though more info is needed. I've had it happen a few times prior to fixing the issues. Have you noticed your coolant temp while driving during these episodes?

Todd

 

This kinda sounds like what happened to me.
Out and about, stopped for gas, and all of a sudden my '00 just started puking coolant.
It was coming out of the overflow.
Thought to myself that is new. LOL.
Figured just cause it was cheap throw a new cap on her.
Sure enough.

 

Yeah, my 90 XJ did the same thing on a mild offroad adventure. Bad oval shaped coolant bottle and a cracked radiator cap. Filled it up with water and running fine with OAT in the mid nineties low 100's here in the PNW.

 

1.) I don't think so, but will confirm next drive.
2.) Will do. Thank you.


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#2
exasemech
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Join Date: Sep 2016
Location: Very far western Maryland
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0
Default1 any coolant on the passenger side floor/carpet?

2 after/during one of your drives use a flashlight and look low on the passenger side firewall and see if coolant is coming out of the HVAC box drain

 

Coolant temp stayed consistent at ~195º. I recently replaced the thermostat (and no, coolant was not leaking from there) so I've been paying attention to that temp. Thanks for the reply.

 

That seems reasonable to me. I'll definitely monitor that cap...for $8 I'll probably just replace it for good measure. Thanks for the reply.

 

I can't believe how prices have gone up.
Was awhile ago and thinking paid less then $3.
But that was with my discount at the auto parts store used to work at so.....

 

Check the rubber line from the cap to the overflow bottle. I've seen that split before and it'll leak once it gets hot.

 

Also might want to check your heater hoses and clamps at the firewall.

 

Recommend stant radiator cap and stant 195 degree thermostat. I change caps on my XJ's every summer.(cheap investment)

 

Is the water pump newer? I know they tend to shed the inner blades and then cause the fluid to not move correctly... leading to the coolant puking out the overflow .

 

Have you verified where the coolant comes from? If it's from the overflow reservoir, a bad radiator cap can do this.

While driving, coolant pumps through the system maintaining temp. Once you shut off, the pump stops and coolant sits in the block and heads and can heat up even more. If the cap is weak enough, the extra pressure bleeds off and the "hot spot" can boil and rapidly push coolant past the cap and into the bottle. Get a good cap.

A pressure test of your cooling system would also be a good step.

 

Taking a gander from under your Jeep would be the first thing I'd recommend. Where is the fluid coming from?
Seems silly for us to throw out all sorts of good recommendations and scenarios when the Jeep is in your yard.........just sayin'.