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4.0L Water Pump Replacement

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65K views 18 replies 15 participants last post by  Jgt1266  
#1 ·
Does anybody have a write up or pictures of how to replace the waterpump on an 03 WJ 4.0L? Whats everybody using for replacement brand?
 
#2 ·
I used MasterPro Select from O'reilly Auto.

It's quite a simple procedure. Basically, you take off the belt, unbolt the 4 bolts holding the pulley on, pop the pulley off, remove the hoses that are clamped onto the water pump, then remove the bolts holding the water pump on. Clean it up and slap the new one on (with a gasket of course). When you clean it, be sure both surfaces are free of any old gasket. Also, you may want to stuff a shop towel or two into the hole in the head to avoid getting old gasket material in there while you clean it. On reassembly, I think I went above and beyond and also used a little RTV along with the new gasket to ensure I would have no leaks. You will need to transfer the old pulley and the metal tube from the old pump to the new pump as well.

At this point, I would consider a new thermostat and flushing the cooling system and refilling with a 50/50 mixture of Zerex G-05/Water.

Here's a picture of the water pump. The thermostat is right above the water pump.

Image
 
#4 ·
Ah very good point!
 
#6 ·
I've used GMB water pump's from Advance Auto Parts on both WJ's and been happy so far. Plus if you order online using Promotion: CCABIN
$10 off orders of $30 or more - $20 off orders of $50 or more - $40 off orders of $100 or more!! Just order online, get the discount and designate to pick up the parts at your neighborhood store. So your ~$57 WP is ~$37.

Good luck...
 
#9 ·
It sounds simple on paper or computer screen. Mine was fun. It took about 3 or so hours. Then again I have the tow package so I have two fans plus trans cooler.

Just from my experience go a head and replace the radiator and hoses. I skimped on the radiator and was pulling it about two weeks later.

If its worth doing once its worth doing right!!!
 
#10 ·
its easier than you think, i did mine with the fan out (was also replacing it) so it made it easier, and i also used the GMB new (not reman) water pump from advance, only advice ill give you is DO NOT just use the gasket, put some rtv (they will give you the right stuff) on the pump where the gasket goes, then put the gasket on then put more sealant on top of the gasket, and like everyone else said, put the metal pipe on before you install the new pump (personally i just got a new pipe from the dealer, was about $20) and the bolt torque is 22 ft lbs on the bolts for the pump, id suggest while your in there getting a new t-stat, its an easy 2 bolts, and only use mopar coolant, should be there 5year/100k coolant
 
#11 ·
kc2mrg said:
...and only use mopar coolant, should be there 5year/100k coolant
Zerex G-05 fits Mopar's standards...
 
#12 ·
hmm... didnt know that, thanks for the info, it was just easier for me to buzz down to the jeep dealer down the road and get there stuff, just what ever you do, do not mix different color coolants!
 
#13 ·
Believe it or not I've *heard* color doesn't necessarily designate what blend you have. But yes, a good rule of thumb is: Never mix colors. Safest bet.
 
#16 ·
I put the 90 degree tube on a tried to get the pump on but I had to loosen that tube a 3/4 of a turn and then tightin it a half turn... will this cause a leak? And also how can I get the belt back on I took the pulley off to the left but now its tight getting on. I am working on a 4.0L 98 jeep grand cherokee
 
#18 ·
On your 98 ZJ 4.0 you wrench the bolt that goes through the pulley (belt tensioner) clockwise to loosen/get play to squeeze the belt on...it's recommend on this 4.0 setup to start the belt on the crank pulley.

On the tube ...it's already on there...start and see if it leaks....I put gasket adhesive on the threads of mine.