For starters I have a new radiator, new water pump, new thermostat, and new hoses all done within the last year since I bought it. A month or so ago I noticed the thermostat housing was leaking, so took it of and put new gasket material on it, no more leak. Then the leak moves on to the main radiator hose, clamp wasn't put on tight enough, so tightened the clamp, no more leak from there. So I fill up the overflow bottle to the max line with the engine cold. A week later, the level is at the min line with the engine cold. There is no visible coolant in the engine bay, it is bone dry in there. There is no coolant on the dipstick and there are zero visible drops of fluid of any kind underneath the vehicle. The system has been burped so that shouldn't be the problem. Where is the coolant going? Am I missing something obvious? The engine has never overheated and the temp stays pretty steady at 195 now that those two previous mentioned leaks have been fixed. Any help here would be greatly appreciated, as I am at my wits end with the mystery of the vanishing coolant.

 

I would refill it to the max line and see if it stays steady. Might of been the system was burping it's self over that 1st week, even though you say you burped it.

 

Not likely, but might as well check your oil, make sure it isn't there.

Edit: You should also check the connections to the heater control valve (I think that is the name) located about a foot from your firewall by the fill tank, has vacuum line running into the top of it, with I think about 4 hoses connecting to it. If yours is stock, it is plastic and a piece of garbage, mine broke, and literally disintegrated when I was replacing it. Even the new one is leaking a bit for me, but blows back and down on the oil filter, but never shows on the ground.

 

^^X2 on the heater control valve. Also, check the floor on the passenger side to make sure your heater core is not leaking...

 

Hi,
I recall a problem with a porous head casting that was located by putting dye in the anti freeze and viewing the top of the head under the valve cover with a blacklight and special glasses.

Dick Kuehn, Albany NY

2000 Cherokee Sport

 

ok, definitely not in the oil. Also doesn't appear to be a leaking heater core. Going to change the heater control valve, as there are some dried coolant drips around the hoses, also, there appears to be moisture running down onto the starter and in that general area. I can't tell if it's coolant or old oil/grease as it has mixed and appears brown with no distinctive smell. Hopefully I can get that changed this weekend. I will let you guys know how it turns out. Thanks for the ideas.

Edit: I did also bring the level up to full on the reservoir and will continue to monitor it until the weekend.

 

Antifreeze leaks can be hard to find. Especially small ones. I've found the best technique is to get the vehicle up on a hoist or ramps, and use a good light. Do so with a hot engine where the cooling system is fully pressurized. Look for clues like white/green debris left over where the leak is taking place.

Still stuck? Get a cooling system pressure tester. Some parts stores will rent you this tool. They can be very helpful here. Worst case, there is a dye that can be added to the radiator, and then use a special light and perform an inspection with a special blacklight and the light will show any leaks.

Good luck.

 

Update:

Ok filled it back to the full line 2 days ago. Drove to work yesterday, everything normal. Talked to my mechanic buddy and he suggested a few things as well. 1st we wrapped a bunch of paper towels around the heater control valve, and secondly to watch for white smoke.

There is no smoke whatsoever coming from the Jeep, white or any other color. Drove home everything was fine. I pulled the paper towel out and there was 0 antifreeze on it, and the reservoir was a full 2 inches above the full line(normal for hot fluid) as I pushed it a little harder than normal on the way home to try and get it to leak. I checked it after 4-5 hours after I got home and the reservoir is right back to where I filled it too. Same this morning. Drove to work today and same thing, normal, after several hours the level returned to the spot I filled it to. So I am at a loss. Perhaps it wasn't properly burped, I don't know. At this point all I can do is keep an eye on it and see what happens. As it appears now there is no leak.

Also tracked down the moisture I found, it appears a tiny bit of oil is leaking from the piece that the oil filter mounts to. It looks to be leaking from the connection to the block. Are these hard or expensive to replace?

 

i would not hurt to have the system pressure checked including the cap , helps to have a pc of mind

 

I did mine this spring, was not a hard job. I bought the o-ring kit from the local Jeep dealer ($6) and a T-60 Torx 1/2" drive socket from Advance Auto Parts ($6 Gear Wrench brand) The T-60 popped out of the scocket real easy and I used a 1/2" wrench with a cheater bar to loosen the adaptor bolt. Remove the oil filter first. No need to remove the engine mount.