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  1. #1

    Default how to change a water pump

    Lets change a water pump!

    Open hood disconnect battery just to be safe

    Take off the intake hose/resonator connecting the throttle body and the air box. Loosen the C-clamps and gently pull the hose ends off the connectors.

    Take off the fan cowl. There are two 10mm screws on the inside top of the upper cowl and 2 pop-its on the seam holding the upper cowl to the lower on each side. All you need to do is get a flat blade screwdriver underneath the plastic head and gently lift. Remove the pop its and gently pull out the holder clamps from the upper radiator hose and lift it right out.

    You are now at what can be the hardest part the fan clutch assembly. There are special tools (that work like crap) to get the fan off the water pump but could not get the one I borrowed from pep boys to work. I tried putting a large adjustable on the nut and hitting it with a hammer (hit towards the passenger side) but if your belt is loose or its been on there for 150,000 miles then you will likely be out of luck. There are 4 holes in the face of the pulley. I took a pair of bent needle nose pliers and stuck the ends into two of the holes. I then used a pair of vice grips to hold the pliers and then hit the adjustable wrench and that broke the nut loose. Remove by spinning off the water pump pulley.

    Here is a pic of the front with the Fan off

    Next take off the serpentine belt. Make sure you can read the belt diagram or draw it out on paper/take a picture. The belt tensioner fits a 15mm socket. I used a ratchet compressing the tensioner and removing the belt. It is a good idea to replace the belts while you are in there.

    With the belt off you can now remove the belt tensioner, which is directly attached to the water pump. 10mm socket

    Now drain the coolant. Open the overflow at the top. On the passenger side of the radiator disconnect the lower radiator hose by using a vice grip to compress the clamp and pull it off the neck of the radiator. Gently pull the hose off and make sure you have a catch pan that can hold 3-4 gallons of fluid.

    I replaced both my upper and lower radiator hoses as well given their age.

    When the system is drained remove the thermostat housing also attached to the water pump 10mm socket. I bought a new one to replace it as I was already in there. This will leak so keep you catch can under the area.

    Disconnect the heater hoses and upper radiator hose from the water pump using a vice grip to work the clamps. Be patient and work the hoses off the pump and remember there will be fluid move your catch pan.

    Remove the water pump 10 mm socket 6 bolts. Just look at your new one you will see where they are. Here is a pic with the pump off

    There are two openings into the block that make contact with the water pump and have gaskets. Make sure to scrape off all of the old gasket material off the engine.

    When cleaned up grab the new water pump and thread the bolts in. place the gaskets on the backside using the bolts to hold them in place. Tighten the blots hand tight then torque to 22 ft lbs.

    Now its time to reverse the steps

    Put the thermostat housing (or new thermostat housing) on the new water pump
    Put the belt tensioner back on the new water pump

    Attach the heater hoses and lower radiator hose (mine was new) to the new water pump.

    Put the serpentine belt back on (AC belt too if you are replacing both)

    Put the fan clutch assembly on the new water pump pulley. I used the same make-shift plier gizmo to hold the pulley so I could tighten the fan properly.

    Put the fan cowl back on

    Attach the upper radiator hose (mine was new)

    Put the air intake hose/resonator back on the air box and throttle body

    Fill the system with 50% dexcool 50% distilled water (around 3 gallons)

    Reconnect the battery

    Start engine run for 20 seconds or so to move coolant around.

    Add fluid till you are at max cold level, run until you get to operating temperature, check for heat and give it a test drive.

    Next day check the level of fluid cold and add if needed.

    I am not a mechanic and it took about 5 hours taking my time & two trips for incorrect parts. The fan clutch took 90 minutes all on its own. That was very frustrating. Having a second set of hands is helpful.
    1995 Saturn Sw1 196K and counting
    2001 Suburban LS 150K and counting
    2004 MR2 Spyder 62K and counting
    2007 mini cooper S 60K and counting

  2. #2


    I did one on my 03 a few months back. I too had to make several trips to the parts store as they did not realize that there are 2 different models of pump and thermostat/thermostat housing. The fan clutch was a pain in the rear to ay the least. I did the same thing you did, I rented a worthless tool. I ended up drilling 2 holes in a old carpenter's square. I then notched a small spot out between the holes to fit around the nut for the clutch. I still broke 3 bolts that I had put in the holes in the square then threaded them into the pump pully. It finally came off. Nice write up. Would have loved to have something like this around when I did mine. I had watched a few videos on youtube, but those guys always make it seem like a 5 minute job.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3



    I agree the videos are awesome but I mean one hit with a hammer and the fan comes off...

    I wish

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