Changing the water pump on your 4.0L

As my faithful XJ has grown older over the years, it’s started to show signs of its age (and probably the results of all the trail use it’s seen). The radiator has been replaced, the exhaust manifold cracked and was replaced, the power windows and locks are slowing, and most recently, the water pump started to die. Thankfully, whoever originally designed water pumps for engines added in an early-warning feature to let you know when the pump is starting to go bad. On the front of the pump there’s a weep hole just below the input shaft, when the internal seals start to wear out, coolant will leak (or weep) out of this hole, letting you know it’s time for a new water pump.

drip, drip, drip…

well that’s not good…

When I first noticed the small random puddles of coolant that appeared under my Jeep if it had been sitting for a while, I couldn’t figure out where it was coming from. The puddles were under the axle, under the back of the oil pan, or under parts of the steering linkages. What was happening was coolant was slowly leaking out of the weep hole on the front of the water pump, and then running along the top of the oil pan and down the back, or dripping down onto the steering linkages and running down them before dripping onto the ground. Once I finally traced the coolant back to the pump and determined it wasn’t the lower radiator hose that was leaking, I set about researching my options.

the back of the pump

the weep hole

My first thought was to get a FlowKooler pump, since they’re the big name in aftermarket performance water pumps and because I generally prefer not to replace a broken or worn out factory part with another factory part (if you’re going to be replacing it anyway, why not upgrade, right?). So I started asking around on the various internet forums and email lists I participate on, and the general consensus was to simply stick with a factory replacement pump. I don’t think anyone ever said anything bad about the performance pumps, only that at $100+, they just weren’t worth it when compared to $40 or less for a regular replacement pump (that usually carries a lifetime warranty). A good friend of mine had already replaced the water pump on his XJ before, so I enlisted his help and we set out to AutoZone to grab some new parts.

The new pump only set me back about $25 plus tax, and did in fact come with a lifetime warranty. I also opted to pick up a new thermostat (192*), thermostat housing gasket, lower radiator hose, some hose clamps, a tube of gasket maker for water pumps and thermostat housings, and of course a gallon of coolant. All together I probably didn’t spend much more than $60 for everything.

On to the install…

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11 Comments so far

  1. Jay July 25th, 2010 10:42 am

    You did a great job, i did not have to loosen my power steering pump though. I did have to loosen the tension pulley of course. If you leave the belt tension on then remove the 4 bolts from the pulley of the water pump that makes it easier.

    Besides that..Spot on. Great job.


  2. Damageinc August 4th, 2010 9:43 am

    Nice job on the write up. I don’t fully understand this comment:
    “i did not have to loosen my power steering pump though. I did have to loosen the tension pulley of course. If you leave the belt tension on then remove the 4 bolts from the pulley of the water pump that makes it easier.”

    …and wanted to know if you can explain a questions for me :
    If you leave the belt tension on(because the tension pulley wasn’t removed?) then how do you put the water pump pulley back on the belt (or remove it even?) with tension on the belt.
    I have a ’94 Cherokee that I have replaced just about everything on and was taking it in for inspection (then sale) when this started happening…

  3. Jeepin Jason August 4th, 2010 10:09 am

    My guess is that JJ has a late model XJ — they have a dedicated tensioner pulley, vs our older model XJs that use the water pump itself to set the belt tension.

    I’m also guessing he recommended leaving the tension on the belt only initially, long enough to hold the water pump pulley stationary, making it easier to loosen the pulley bolts without using the two-wrench or vise-grip method I used (kinda like how it’s a lot easier to loosen the lugnuts on the front wheels if you’ve still got some weight on them to hold them stationary).

  4. Kennie Augustus September 1st, 2010 9:21 pm

    Very Nice Job on the write up and Pics you explained everything with very precise information. Im just heading back out to the guarage to put it all back together. I did the same thing you did as far as buying the parts I figured why I had the whole thing tour apart I might as well change the thermostate and the belt had some signs of ware so I picked up a new one. I probably should have read your artical first I ended up removing the radiator which took a little more time but gave me plunty of room to work and I gave the radiator a good cleaning inside and out. There is only one differnce with mine and Im not sure if its the problem or not but I checked for leaks after removing the pump and found I had one down on the very bottom of the time cover so I asked at autozone what they thought it might be and the said it may be the time cover gasket it was fairly cheap so I bought the kit I havent removed it yet but I hope this isnt going to be a waist of time but like you mentioned you didnt like to have leaks when you were done. I dont either anyway just wanted to say nice job again and hopefully you read this and maybe someone will have the same experience with the timeing cover. Well better go, excelent JOB oh ya one note if you do have to ever remove the radiator dont fight it like I did for a half hour remove the top support that the hood latch is attached to 6 bolts if I remember right. Best of LUCK and Thanks Again

  5. Michelle September 29th, 2010 3:44 am

    How long does it tae to change out the water pump. The tention belt looks as if that is my only struggle. Is there anything else that I have to remove other than the tension belt and water pump itself?

  6. Michelle September 29th, 2010 3:45 am

    oops How long does it take

  7. kevin December 5th, 2010 7:06 am

    this is a flawless walk thru to install a water pump

  8. chris March 21st, 2011 10:23 am

    im goona be doing a waterpump replacement on my 95 cherokee sport, i searched pumps online and found some that the website says fits my jeep, however customer reviews says that they dont pump water and maybe that the pump the opposite way, how do i know im purchasing the right part

  9. August August 26th, 2012 7:26 pm

    Gr8 write up. I will be replacing the
    waterpump 9/1/12.for my friend. Thank you for allyour help. It would be great to know exactly.what tools are needed for the job. Its metric? 7-8-9-10-12 mm.?

  10. […] pulley when on the vehicle where one just cannot see a drip forthcoming at that point. Weep Hole: I have to think hard because working stiffs like me have to plan every second of time away from […]

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