Hi there, I am a new member and I recently purchased a 2002 Grand Cherokee.At about day 3 the low coolant indicator comes on.I added coolant and checked reservoir again today.It might be down a bit ,but am not sure . Added up to full mark today.Is this an issue with 02 models also ? ( 4.0 )

You know? I shouldn't have bragged about my WJ being so reliable. Last night while delivering newspapers in a blinding snow storm, I happened to notice my "low coolant" warning come on. I didn't think too much about it until I saw the temp guage needle a little higher than it should be. I stopped and popped the hood. The heater supply hose had a small split in it where the clamp was at the thermostat. Likely, there was enough slack in the hose so I was able to cut off a 2" section and reattach it. I went to the nearest convenience store and bought some coolant. It stayed normal for the rest of the route, although the heat was lukewarm. It's currently parked in my driveway with 2" of snow on it and probably stay that way for another day.

The 2 radiator hoses were new last year, but the heater hoses are brittle with age. I should have replaced them with the rad hoses.

Any ever find the vanishment? I gave up trying to fix it , I have just been living with it. I have noticed that in these warmer months it goes longer before refills. I find that odd. I would think colder months it would do that.

It still bugs me, I would love to get this mystery solved

Yeah, mine doesn't seem to be getting worse so I'll just live with it until something is obviously wrong with it. The only problem I've had with it is an occasional "false" start. That is, it doesn't start when I release the key before the usual time it fires. Usually it will fire after about 2 turns of the starter. Sometimes when it's hot, it requires more cranking time. Not excessive. but more than 2 starter turns. I guess I'm expecting too much from a motor with 157K on it. It's been so damned reliable, even at sub-zero weather, that I'm getting complacent.

I'm going to try some other form of cap for my reservoir. That's problematical because it doesn't have threads on it. This is just to see if the loss IS evaporation. Maybe I'll look in the JY for a reservoir from an XJ with a threaded cap.

My 2 cents...Cracked head.

Mine had the same mysterious coolant leak. Worse in winter, no sign of leak. Verdict?? Water pump....yes it was leaking at weep hole but never at idle speed. It was always dry when I looked at it. How old is your pump?

You know, that is a possibility! I do occasionally get a slight whiff of coolant when I walk around the front but never see any leaks. As far as I know, the water pump is original with 157K on it. I suppose I could change it and see if it makes a difference, but it's a lot of work if it isn't the problem.

I am due for a complete system flush, thermostat, and heater hose replacement before winter anyhow. I guess I could add the water pump and serp belt to the parts list.

Question, was your leak the same as mine? What happens to me is: my reservoir empty's it self out, though my radiator stays full. So I wouldn't think the water pump would be my problem. So if that is the same as you then I will try it.

Never see it mixing with oil though, or weird colored/smelling smoke from exhaust. so doubtful it is my issue

Mine has always had false starts if you don't prep the fuel pump 3 times first (turn the key to ignition 3 times then turn it over) but that's a well known issue with these things, even XJ's. If you replaced entire fuel pump system (not just pump) it would fix that.

A threaded cap for these would be smart, even of its unreleased to this issue.

Yes it was. Reservoir will empty for any leak.

I just wanted to make sure your radiator was staying full,like mine.

But good enough, I am going to look into water pump then.