Phantom Coolant Leak. HELP. I have searched!

OK. First the specs...

1990 Jeep Cherokee
Automatic
Stock Everything

I have noticed a small puddle of coolant in the mornings... just a slow drip. I can't figure out where it is coming from. When I looked under the engine, it doesn't look like it is coming from the front of the engine compartment (water pump, radiator etc)... but more on the side near the exhaust manifold. I can't see too much under there, but am pretty sure it is leaking from that general direction.

When I am driving, or running the car it doesn't seem to leak... only when it is sitting there. I am thinking it may have something to do with the engine cooling down after reaching temp. The metal contracting or something. Could this be a freeze plug issue? If anyone can shed any light on this, I would greatly appreciate it.

thanks.

I´m pretty sure that one of your engine block seals is passing away. I think they are made of cooper or any other soft metal.
Its a cheap part but you will have to remove the header and intake manifold in order to work in the area.

Swap all of them

Regards

Check the weep hole on the water pump. They can leak and run along flange of engine to back or other places.

Engine off--Mirror, flashlight and quick wipe with a finger (weep hole),will confirm where the leak is at.

Good Luck

thanks... will check and let you know what I find out

Check the lower radiator hose for a hole. Also the left side of the radiator.

Yeah, if the weep hole is being utilized, it will be clean with dirty edges. What happens is not only does the coolant run down a unique path, but he fan influences the drop off point.

The reason it doesn't leak when running is that the fan probably blows the coolant back and it becomes part of your perpetual under coating receipe, coolant, oil, and transmission fluid. Or, at temp, it closes off.

If it is coming out of the weep hole, get a water pump. I replaced 3 on my 90 since I bought it new. The last was a KoolFlow which has lasted the longest.

Borrow/rent a pressure tester from a parts store. Pump up the system to whatever your system needs, can be found on the radiator cap. Then look around for leaks and listen for pressure escaping.

IF it is the freeze plugs this tool allows you to replace most plugs without removing headers:

http://www.sjdiscounttools.com/atd-5270.html

Get your vehicle up on a hoist. Leaks are much easier to locate when you have better access and a good light to inspect.

Leaks can migrate....don't be fooled. Where they "drip" isn't always where they leak.

Lot of possible causes here so don't assume anything.

Good luck and let us know what you find!

birchlakeXJ said:

Get your vehicle up on a hoist. Leaks are much easier to locate when you have better access and a good light to inspect.

Leaks can migrate....don't be fooled. Where they "drip" isn't always where they leak.

Lot of possible causes here so don't assume anything.

Good luck and let us know what you find!

Click to expand...

x2, a bright spotlight works wonders.

If you still have problems you can get UV leak detector dye and use that.

thanks everyone... I am going to try to get to this over the weekend. Thanks for all the tips.

I had my 1998 xj leak mysteriously a few months ago. I found it to be the heater core. Unlike most cars which leak onto the floor inside the jeep has a drain pan that leaks coolant to the back of the engine bay. The dead giveaway was moisture and coolant smell coming through the vents. I bypassed mine until I get a new one (we are a very warm climate so heater is not really necessary here!!)

Hope this helps, registered just now to answer your problem. J.

The biggest help in finding a slow leak is a radiator pressure pump which fits on in the cap location. Might be able to rent or borrow one, but they are extremely useful.