Changing the water pump on your 4.0L

The whole procedure is really pretty straight forward, and you don’t need any special tools to change out the water pump, just an regular assortment of metric wrenches and sockets. You’ll also need a socket extension to get to the bolts around the bottom and far side of the water pump, and a pair of vise grips might come in handy too as you’ll see later.

Before you get started pulling stuff off, go ahead and start draining the radiator, that way hopefully it’ll be done by the time you’re ready to pull the pump. The drain is on the lower passenger side corner of the radiator, you’ll probably need to pull off the grill to get to it. Be sure to check your local or state regulations regarding the disposal of used engine coolant.

You’ll want to start by removing your intake and auxiliary electric cooling fan to free up some work space. Once those are out of the way, loosen the bolts on the front, side, and back of the power steering pump that are used to tension the serpentine belt, and then pull the belt out.

The next order is business is to unbolt the power steering pump and its mounting bracket and get them out of the way. There’s a bolt hidden behind the pump that helps hold the mounting bracket to the engine, so you’ve got to swing the steering pump all the way over to get behind it – that or just completely unbolt the pump from the bracket.

You can change out the water pump without removing the thermostat housing, but it makes life a lot easier if you do remove it. Besides, it’s probably time to replace that old thermostat anyway… There’s probably going to be some coolant still in the upper part of the block, so don’t be surprised if coolant starts leaking everywhere once you start removing the thermostat housing.
While you’ve already got coolant dribbling everywhere anyway, now’s probably a good time to go ahead and pull the lower radiator hose too (which is probably also still full of coolant).

Once you’ve got the thermostat housing out of the way, you’ll notice a long metal tube shaped kind of like a hockey stick coming out of the top of the water pump and going up to the side of the valve cover. You’ll need to unhook the heater hose that’s on the top end of that tube.

Now it’s time to pull the pulley off the water pump, because the 2 of the 4 bolts holding the water pump to the block are behind the pulley. By putting wrenches on two bolts at a time, you can loosen 3 of the 4 bolts holding the pulley on the pump. The 4th bolt can be a bit tricky though, that’s where the vise grips I mentioned earlier come into play. Grab the pulley with the
vise grips, being careful not to damage the surface where the serpentine belt rides. Now that you’ve got a good handle on the pulley, you can loosen and remove that last bolt.

The pulley should pop off the pump without too much trouble, but it may need a little persuasion by a small pry bar or big screwdriver. From here you can now remove the 4 bolts holding the pump to the block and pull the pump out.

With the pump off the engine, you can remove the metal tube and swap it onto the new pump. This was easy on mine, but my friend didn’t have an easy of a job on his ’89 because the tube on his pump lacked the “nut” that mine had, so he had to use vise grips and heat to get the tube unscrewed. When you put the tub on the new pump, use some Teflon tape on the threads and make
sure you get it turned to the right position before you bolt the new pump up to the engine.

Before you go putting everything back together, you’ll need to spend some time scraping all the old gasket material off the thermostat housing and off the block. Make sure you’ve got a good, sharp gasket scraper, and you’ll probably want to stuff something into the coolant ports in the block so you don’t wind up with bits of gasket material all inside your engine’s cooling system.

Now it’s just a matter of putting everything back together. Even though I had new gaskets for the water pump and thermostat housing, I still used some of the RTV gasket maker on both sides of the gaskets, to make sure everything was nice and sealed up for no leaks. Remember to bolt the new water pump to the engine before you put the pulley on it. Once you’ve got everything bolted back into place, fill up the cooling system with coolant and distilled water, check for leaks or loose hose clamps, and you’re on your way!

Total time for the install was about 3 hours, and we were taking our time and taking photos.

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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.?

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