GMC Suburban Water Pump Replacement

I helped Jack replace the water pump on his Suburban this afternoon. It has been leaking coolant for a while and it was slowly getting worse. He had replaced the water pump once before and it looked like there might be some seepage where the pump bolts to the block. He had already removed the top half of the fan shroud and the serpentine belt.

The next step was to remove the fan clutch from the water pump shaft. Used to be this was done with four small bolts. Now the hub of the fan clutch threads onto the front of the water pump shaft. You need a big wrench to grip the hexagon shaped hub and something to hold the water pump pulley still. He had a piece of steel strap with a hole in one end. Take one of the bolts holding the pulley and use it to attach the strap. The strap will swing around until in contacts one of the other three bolts holding the pulley. Now you can hold the pulley and use the wrench to loosen the hub.

We used a 20" adjustable wrench and the head was so fat it would barely fit in the space between the fan and the pulley. Aside from dropping several bolts into abyss, getting this fan clutch off was the toughest job. A thinner wrench would have made it easier. So would not dropping the bolts.

We had to take off one idler pulley in order to loosen a bracket holding a heater hose because we did not have a 10mm socket. When we pulled the idler pulley off I noticed a bunch of aluminum flakes inside the hole. We blew it out with air and mixed up some epoxy with aluminum powder and put that in the hole before we put the screw back in.

There was one big hose and two small hoses connected to the pump. They were held in place with spring clamps. A small pair of channel-locks worked to undo the clamps and then we used them to twist the hoses to break them loose from the pipes. After that they pushed off easily. Pushed, that is, not pulled. Pulling didn't work. The small hoses were kind of tore up by the pliers so we asked for some new ones at the auto parts store (generic, not the dealer), and surprise! They had them. Since we were going to all this trouble, Jack elected to replace the pump, the serpentine belt and the small, short, heater hoses, but not the big radiator hose.

We recovered all of the dropped bolts except for two screws for the fan shroud, and we found some adequate replacements in the garage. Unfortunately, the only washers we found were the wrong color: silver instead of black. I assured Jack that they wouldn't hurt the motor. Locating the lost screws was complicated by the fact that the vehicle is equipped with a winch that is concealed behind the front bumper.

After we had everything buttoned up and the coolant system topped, Jack fired it up, and everything seemed to be running smoothly. It was very gratifying to be able to do some mechanical work and have it turn out successfully.

Update: Part two of this story here.

Update December 2016 replaced missing pictures.