Basslicks

Don't trouble yourself with finding an OE MOPAR pump... the Duralast water pumps that AZ sells are exactly the same. Found that out the hard way when I bought a MOPAR unit and the bearing was bad outta the box. RockAuto let me down with this one. ALL of the water pumps they list are for ALL years 87-01, but the MOPAR pump was only listed for 00-01.... so because it wasn't "labeled" for my Jeep, they didn't honor the warranty.

Luckily, I had bought a Duralast from AZ back when I first bought the Jeep and it has a lifetime warranty. I pulled the pump out of the box and compared it to the MOPAR pump - they're exactly the same. Right down to the casting marks and numbers.

cruiser54

Like this?

Bucko

Pretty much exactly this.

Basslicks

Weep hole. Water (and coolant, obviously) runs out the weep hole and down the lower rad hose.

Time for a new water pump.

Chick-N-Picker

Id listen to Cruiser and switch to the open cooling system. You cant go wrong with listening to him, if you understand his instructions lol.

Ive owned 2 jeeps. A 94 and 89. I switched my 89 to an open cooling in July. My thought was "Where have you been old friend?"

Basslicks

True story.

Bucko

Took a better look today, still not clear if the pump is leaking or just the lower hose. The pump body (not that I can see much of it) looks dry until near where the lower hose attaches. I can't see the weep hole, too much stuff in the way - unless I'm looking in the wrong spot - but I don't see any crusty reside anywhere. I pulled the lower hose off at the pump about a year ago - the last time I changed the coolant - maybe I put to much of a strain on the hose pulling it off and it's sprung a leak (I know - wishful thinking).

I'm loath to pull the pump off if I don't have too. The pump has been on the jeep since new and getting all the required nuts and bolts off could be a real pain in the *** and I'm not confident I won't break a bunch in the process, which would, for all intents and purposes, 'total' the jeep.

I think I'm going to go ahead and order a pump and a hose (and a serpentine belt) and just try swapping the hose (and the belt) to see if that fixes the leak before tackling the pump.

Basslicks

I doubt you'll be able to see the weep hole unless you use an inspection mirror. View is obstructed by the harmonic balancer and the pulley on the water pump.

Bucko

Yea, I was all over the mirror thing but sill couldn't see anything useful.

Then, I remember I bought a really cheap electronic bore-scope about 5 years ago and haven't seen it since . Went looking for it and found it! Sure enough there's some white crap up in there - kind of hard to tell as the borescope is a bit disorientating but i think it's probably dried coolant. Anyway, I'll order the new pump and take off the pulley first which should make things a lot clearer.

Chick-N-Picker

Changing the water pump isnt too bad.

'90Cherokee

I have a closed system and it works fine, I won't change it unless it becomes a problem. I've had no issues with filling/burping and find it easier than the open systems. The majority of modern systems are closed too and most don't have issues. That said, I trust Cruiser and maybe there's just a problem with this particular closed system.

As for the rad, I think the original is an all metal soldered copper/brass rad., at least that's what's in mine. If that's what you have and it's leaking you could take it to a rad. shop and have it repaired. If it is a soldered rad. it's been said that some of the modern long life coolants don't protect the solder, or maybe even attack it, so I use the old style coolant in all my soldered rad. vehicles; I have more of those than I do plastic/aluminum rads. Even if the rad. is changed to aluminum do consider the soldered heater core.

Basslicks

Most newer systems have a bleeder valve on the block which makes the process much easier.

The PITA comes into play with newer high-mileage vehicles that might have a "pinhole" leak. The leak is so slow you don't notice, but since it allows air into the closed system, it makes a mountain out of a molehill pretty quick.

'90Cherokee

Not most; few, if any, closed systems have a bleeder valve. I see them on open systems quite often. I can't think of a single closed system with a bleeder or a need to be bled/vented, tho they might exist. There's lots of open systems that need to be bled/vented. Those can be a big problem with a small leak since they'll become air locked and overheat, often without even indicating on the gauge because the coolant won't reach the sensor. Since most closed systems are self-bleeding, including the early XJ, a pin hole leak is less of a problem.

cruiser54

We are dealing with a horrible case of this:

MayerMR

I feel like it's important that we all take a few days to mull the graph Cruiser just posted...