View Full Version : Coolant leaking from behind waterpump

October 7th, 2006, 12:33
Hi All,

My wife came back the oter day with the news that the jeep was loosing fluids. I checked it and it turns out that coolant comes from the water pomp. It leaks from between the waterpomp and the engine. The leaking does not start untill the car warms up a little (if I let her idle at 1500rpm it takes about a minute or two until it starts). There does seem to be pressure on the cooling system but since I checked that just by squeezing the lines I am unsure whether or not that is sufficient. So does the leaking indicate a gasket failure or is it likely to be more serious and indicates that the pump is probably gone. On the other hand, if I go in there and replace the gasket I might as well do the pump at the same time right? Since I really don't know how long it has been in the car.

If I need a new pump, what would be the best place to shop? Should I buy new or rebuild? Any general advice to go about this job, possible pittfalls?

Thanks for any info on this. As I have never worked on the waterpump before any pointers would be helpful!


October 7th, 2006, 12:58
There is a weep hole on the back of the pump. When it's starting to go, you'll likely see some fluid come from there. See if you can look behind it and tell if that's where it's coming from. It could be a gasket. The pump isn't terribly expensive so if it were mine, I'd maybe consider doing it all together. I got mine from NAPA and it was rebuilt. Just make sure you take the core in with you and match it against the new one and make sure the impellers are the same.

When I did mine I also installed new hoses, and thermostat too. I actually did the radiator and thermostat housing as well but I was having other issues too. The job really isn't all that difficult. Make sure you get all the old gasket off and use distilled water.


October 7th, 2006, 13:13
Weeping hole is right!!! I just did my water pump last night. It looked like the lower rad hose was leaking but it was coming out of the weeping hole. Took us about 1.5hrs to change it because we were also tinkering with the rear brakes and eating unnecessary amounts of food. :yelclap: Fairly easy and straight forward process. New pump cost me $55 no a reman.

October 7th, 2006, 13:45
Thanks guys! Can't really see if it comes out of the hole or not. Probably is but I am unable to locate it with everything in place. You are probably right that in any case I may as well put in a new pump. I will also do the thermostat while I am at it. So just get the stuff from autozone or are there particular brands to shop for? I wanted to buy the new pump and thermostat today and work on it next weekend, but I guess it's better to change the order and first take off the old stuff to make sure I get the right new stuff, right?


October 7th, 2006, 13:49
You'll be fine getting it at AZ. I don't think brand is gonna be a huge issue. I used the one they handed me. If you want to wait until next weekend just make sure you compare the two before putting the new one on.

October 7th, 2006, 13:59
Thanks. Just one more thing. How do I refill the cooling system after draining it. The Haynes is somewhat confusing. This is what I think I would do, need to know if that makes sense.

I would refill the radiator and fill the overflow bottle till halfway upper-lower mark. Then run the engine for a bit (to let the pump circulate the fluid) and fill up the overflow bottle if more is needed.

Is this ok or is there more magic involved? Does the system get rid of the air in the system automatically? I mean, I take it that after draining you will have some air trapped in it, right?


October 7th, 2006, 14:03
What year?

October 7th, 2006, 14:45
It's a 92, line6 4.0l.

On the same note. I just checked out the drain on the radiator. There's a white drain behind the grill. I assume I drain the fluid by turning the drain out. But then how can I hook that up to a hose to keep the fluid clean for re-use (that's a suggestion I got from the Haynes, which is generally a bit sketchy on the subject). I guess re-using the fluid is a myth then, huh? I simply don't see a way to cleanly catch the fluid coming from the side plug. Any ideas, or just let it flow out, catch it in a bucket or so and dispose of it?


October 7th, 2006, 15:46
I have always just filled the rad up with coolant as high as it will go and then filled the overflow. I do just as you described and have been fine. The last time, I did go back to the rad the next morning and make sure it was full after running it for a day. I've never had any problems with air system.

The drain on the rad:
I usually don't re-use the coolant. It is a mess draining the system and you will probably have it everywhere no matter where you put buckets. I usually just pop the lower rad hose where it connects to the water pump and let it p!ss out.

October 7th, 2006, 19:24
I've just discovered driving rear tires of xj on ramps so motor points downward during flush seemed to remove some crud first flush missed, can't prove that's the reason, but little effort involved.

Anyone find the same thing?!?

October 7th, 2006, 20:05
Usually when the weep hole is leaking you have some time (days, hours?) before you NEED to change out the pump. When I did mine I did a through cooling system clean-out and flush before the original pump came off and kept the water flowing after the pump was off just to be sure. You can see inside the engines water jacket with the pump off and check for crud build-up.

October 7th, 2006, 22:21
Ok, will just pull off the lower hose and drain it there. Will give it a go next weekend (will not drive the car of course this week) since I don't have time earlier for this. Will update on the operation when done!

October 14th, 2006, 17:17
Hi guys,

Well the water pump replacement seems ok. I just ran into a little problem with the piece of pipe that connects from the pump to the heater(?). I had to take it off the pump since it did not come with the new pump. However, the thread on that thing is pretty bad and cleaning it didn't help much. Is this a standard piece of pipe that I can get at the local hardware store or should I buy a threader for this? Anyone know the thread size on that pipe? Anyway, I really like to put everything back together but I think I need to take care on this one. Any suggestions?

October 14th, 2006, 17:40
Are the threads just boogered up? If you can't make that one work then you're probably gonna have to go the dealer or to the boneyard.

October 14th, 2006, 17:52
yeah, probably true. I just want to try and re-thread this one, see if that will make it work. Any change you think? I haven't done much re-threading before and not even sure if that's a good idea at all. Anyway, probably a long shot. Otherwise I'll be off to the pick and pull tomorrow:).


October 14th, 2006, 17:55
Well...is it something that you think you can just get a tap for and clean up the threads? I might try it. Although taps aren't cheap and you could probably get that pipe for a few bucks at the yard.

October 14th, 2006, 18:26
If the threads are rotting, rethreading probably won't help much. If it's just a build up of the sealer they use on the threads from the factory, a wire brush will clean them up good enough.
In a pinch you can use regular old 3/8" water pipe. The threads are standard pipe threads. The 3/8" water pipe does have a slightly smaller inside diameter than the stock piece.
I can't remember if the 92 has the bend at the top of the pipe or not. If it doesn't have the bend, a straight piece of 3/8" pipe will work, if it has the bend you may need an elbow and another nipple or you may run out of heater hose (too short).
I made my last one with a threaded copper end (3/8" pipe thread NPT) a couple of short pieces of copper pipe and an elbow. And soldered the pieces together. They wanted like $40 at my local Jeep dealer for the replacement part.
Sometimes the pipe comes with the water pump, not often, but I've bought the pump and pipe as a unit. it may be worth shopping around a little and asking a few questions.

October 14th, 2006, 20:40
8mud, can you tell me where you got your unit? I am thinking it would be easier for me just to buy a complete kit and return the one that I have. Saves me time, and I get a new pipe on top of that:).

Thanks, Tim

October 14th, 2006, 20:55
i had the same problem with that hose...i just used a small length of heater hose and some fittings to replace the metal hose, and its been fine ever since.... cheap and easy, if you can't find something else...

October 14th, 2006, 20:57
If you are talking about the pipe to the heater hose....go to the parts store and ask for a pipe threaded nipple and get a longer heater hose to compensate. Good luck finding the original pipe anywhere but ordering from Jeep dealer. Or...cut and braze a new pipe thread nipple to the pipe. Or...just use nipple...cut the pipe and use a splice with clamps.

October 14th, 2006, 21:03
yeah, what alohabra said is what i did...thanks for explaining it better, haha

October 15th, 2006, 09:08
Ok guys, thanks for that input. Will try the picknpull today. If nothing there I will buy a nipple (is that something I get at a hardware store or the car parts store?), cut the pipe and connect the two with a fitting (well I guess I'll be off to the hardware store anyway then:)).


October 15th, 2006, 09:17
Yeah...the nipple is 1/2" NPT on one end and a straight on the other. Usually they are brass. Hardware or auto parts store will have plenty...used on older GM and Ford engines all the time. Just get a hose long enough to go from the firewall to the front of the engine and tie wrap it in place. Change the other heater hose while you are at it if it has hardened. Use teflon tape to seal the pipe thread and hose clamp for the hose.

October 15th, 2006, 09:40
Yeah...the nipple is 1/2" NPT on one end and a straight on the other. Usually they are brass. Hardware or auto parts store will have plenty...used on older GM and Ford engines all the time. Just get a hose long enough to go from the firewall to the front of the engine and tie wrap it in place. Change the other heater hose while you are at it if it has hardened. Use teflon tape to seal the pipe thread and hose clamp for the hose.

It's 3/8 inch NPT on any I've ever changed. Hard to tell by looking at it sometimes.

October 15th, 2006, 10:47
It's 3/8 inch NPT on any I've ever changed. Hard to tell by looking at it sometimes.

Thanx..i stand corrected on the size and will make an edit (oops..can't). Those pipe threads are a liitle "oddball" and it is usually best to take a sample with you.

October 15th, 2006, 22:18
Hi guys, job's done!

I went to the hardware store to get the nipple. Then I decided I would have a go at trying to fix the thread with a steel fitting that I could screw onto the pipe in trying to fix the thread (since the pipe material seemed a lot softer than the steel fitting). Doing that a couple of times worked really nicely and for $1.39 I had my own little pipe-threader. Pipe fixed.

After that it was a walk in the park. Got everything back on the car in less than half an hour and ready to roll. Of course I first needed to charge the battery because I left the trunk open and -- since I thought (again) I could handle this one with the battery connected -- the result was a no go on the initial start-trial. The clicking starter relay is starting to become a rather familiar sound since I seem to pull this on myself pretty much everytime I work on the car. Anyway, put the charger to work and an hour later car was running beautifully!

Now here's the thing that surprised me. I thought the water pump wasn't gonna make a difference for the running part of the engine (at least not noticable) but it seems to do so anyway.

In idle it revs slightly lower (I think it is around 600-700 revs, maybe 800) than before (+/- 800-900 revs) and I need to crank less before she starts (which truly amazes me!). I know, doesn't make much sense to me either, but it really seems that way. Any clues?

Temp wise things are much better. Before (we've only had this little truck for three months now) the dial was always around 200-210 and I kind of thought that was the way it ought to be (although of course I should have checked that in the manual, but didn't) and now it's closer to 190-195 where it's supposed to be. Actually, I was so used to the dial sticking close to the vertical (200-210), I thought the engine was too cool. I supposed this improved cooling is either the thermostat (which I also replaced) or the pump, or both. Best of all, no more leaking!

Thanks again for all the help and input. You saved me from many mistakes and I've learned a lot, ranging anywhere from plumbing to inches and bolt sizes. Great!

If you guys have any clue why my car runs different (better?) than before, and how that is possible with just replacing the water pump, please let me know! I am clueless (but happy!).

Blaine B.
October 16th, 2006, 12:29
Replace the water pump. AutoZone has a new duralast pump for around $45.00, I just replaced mine. RTV The gasket on both sides and you should be good to go!

October 16th, 2006, 12:50
Sorry, maybe I wasn't clear on that. I have just replaced the water pump and thermostat. That's where most of this thread was about......teaching me how to do that:).