Ubik

My 98 xj hates water pumps and has gone through four or five in about 8 months. After about 60-90 days it starts dripping coolant from the weep hole in the water pump. I've replaced the water pump two or three times and Dodge has replaced it once. What could be the issue here? Any information would be greatly appreciated. Thanks.

It's 4wd and has the 4.0 liter motor in it.

jordan96xj

Given how simple the water pump is on these, my first concern would be that the belt tension is too tight and it is putting too much pressure on the bearings and seal. My next concern would be the alignment of the belt on the pulley and the possibility that it is riding unevenly on the pulley and putting stress on the bearings/seal. Have you tried different brands? or have they all been the same brand of pump?

Ubik

They have all been different brands--but I can't remember which ones they were. I did however use only the brands you guys recommended.

The belt isn't misaligned but you could be right about the belt tension...though I did use a tension gauge the last time i replaced the pump...

Is it possible to damage the water pump bearing by over-torquing any of the bolts?

My main concern, and maybe I'm overthinking this, is there any way the block could be cracked at the water pump mating surface and only appear as if the water pump's weep hole is leaking when it really isn't? If I remember correctly the weep hole is obscured by the water pump pulley.

tinytrax78

try a flowkooler this time

jordan96xj

No, over-torquing the bolts should not really effect the bearings or seal. Unless the bolts were torqued very unevenly. In general, over-torquing on these components is a good way to have a bolt snap off in the block, so be careful.

Before thinking the block had cracked, I would suspect something more mundane like an uneven mating surface, that is escaping your inspection each time. Like left-over material on the surface, deep scratches from prior cleaning/scraping/grinding, or corrosion causing the surface to not be flat and smooth. Given that it has happened on several brands of pumps, I would very much double/triple check this possibility on the next one.

If there was a mating surface problem, you are correct in that it might be hard to tell the difference between that and something coming out of the weep hole. In order for coolant to get to the weep hole it has to get through the seal, so with that happening multiple times (very rare), it suggests even more that you might be dribbling from the mating surface. When I did mine, I used a little permatex thermostat/water pump gasket compound on the mating surfaces and on the felpro gasket I used. I do this to help compensate for any deep scratches or obstructions on the mating surface that I might have missed. Also, Its not terrible hard to remove the next time I have to do the job.

Are your bolts over-torqued because you were trying to rule out or stop a leak? If it was leaking right from the time you installed it, then it is almost definitely not the bearings/seal.

PatHenry

I agree with Jordan.

Before putting a new water pump in - run a hose through the engine and try to flush as much crap as you can out of there - then use the Permatex (or another high quality water pump/t-stat gasket maker) and follow the instructions carefully.

Ubik

Jordan--I really appreciate all this information. I will put it to good use the next time I swap out the pump.

I didn't intentionally over-torque any bolts to stop or prevent a leak, but I couldn't fit my torque wrench down in there either--and the leaks all took about a month or two to start--except after dodge replaced the pump, then it may have taken three or four months to start leaking, it's been a while.

tinytrax--thanks for the recommendation, I'll look into the flowkooler

Ubik

Will do

jordan96xj

Ok, so if the leaks are taking 2-4 months to return, then that points a little more at belt tension. But still double/triple check that mating surface.

It also makes me concerned that you might be getting high pressure that is failing to be relieved by a properly functioning radiator cap. Do you have problems with overheating from time to time? Though this possibility is a stretch, because the hose connections would almost always leak before a properly installed water pump (it is much more solid and stable than a hose clamp and rubber).

Ubik

As long as I've had it the vehicle has never overheated.