Replacing a water pump can be a daunting task for an amateur mechanic. Of all of the jobs that most backyard variety mechanics do, this one is about as difficult as they come without tearing into the heads or transmission of your car. If you have never had the water pump off on your current vehicle, plan several hours for this job. You may want to keep a log of each step so that you will remember how to put everything back when you are ready to wrap up your project. For the most part, your hands and arms will probably get very dirty during the process of replacing your water pump.
Start by locating the water pump.
On some newer cars, you may not be able to see the water pump because of all of the belts and equipment that will be blocking the view. Water pumps usually sit behind one of the pulleys on the front of your engine. For rear wheel drives, the fan almost always bolts to the water pump pulley. On front wheel drive cars, it will usually be behind a pulley near the middle or center of the engine.
The only obvious thing about a water pump will be the heater hoses coming from it running toward the car’s firewall. These may come off of the bottom of the pump and not be easily visible from above. If all else fails, go to the parts store and ask them for some guidance. They can usually point you in the right direction. On the other hand, if you have this much trouble finding the water pump, you may want to seriously find some help or consider farming this job out to a professional.
Carefully remove anything that is in the way of accessing the water pump.
Water pumps tend to have about 6 to 8 bolts holding them to the engine block with a gasket behind it. You have to reach all of the bolts to remove them. More importantly, you have to be able to position the water pump and gasket properly while inserting the bolts back into the block. This will require as much access as possible to the water pump. Even nimble hands and fingers can have problems getting everything off and on in some of the tight quarters surrounding the water pump. So, keep removing things starting with the belts until you have a relative clear shot at the water pump. As mentioned early, you may need to take notes as you go.
Use a large pan to catch the coolant from your engine.
Place a large pan under the car to try to catch as much coolant as possible when you start removing hoses and the water pump. Because the coolant will be contaminated by the dirt on your motor, it is best to proper dispose of this used coolant and replace it with new coolant at the end of the job.
When the water pump can be accessed, remove any hoses that are attached.
As you remove the hoses, mark them regarding where they hooked to the pump. Keep track of the clamps because you will need them later. Inspect the hoses. If they have any weak spots or bulges, consider replacing them while you have easy access. It is best not to remove the pulley attached to the pump unless you cannot get to all of the bolts with it in the way. If you can avoid removing it, it will be easier to deal with when it is off of the car.
You will almost always need two different size wrenches or sockets to remove a water pump.
For some reason, most car manufacturers enjoy tormenting mechanics by adding in various sized bolts to make you have to use as many tools as possible to do repair work. Water pumps frequently have 4 larger and 4 smaller bolts fastening them to your engine. Make a note of which bolts went into which holes. When the pump is off, remove the pulley. If you have already removed it, make sure that it will fit onto the new water pump. If you had to remove it to get to the bolts, you will want to wait and put it on the new pump after it is installed. Otherwise, bolt it onto the new pump now.
Scrape off the old gasket from the engine block before attaching the new water pump.
Use a scraper and remove the old gasket entirely. This can be a slow process if it is really bonded to your engine block. If you do not get it all off, it will cause your new gasket to leak. So, take your time and do this right. It is better to do it now than to have to repeat the job later.
Use a little gasket sealer to bond the new gasket to the engine block.
Put the gasket sealer evenly around the entire surface that the gasket will cover on the block. Normally, you can place the new gasket onto the sealer, and the sealer will hold it in place for you as you install the new water pump. Use the same sealer and coat the surface of the water pump that will cover the gasket.
Carefully place the water pump onto the gasket.
You will want to do this job slowly because if you bump the gasket too hard, it will shift and none of your bolt holes will be aligned. This can happen and the gasket will seem to look like it is still in place until you start trying to put the bolts back into the block. With the pump against the gasket, insert two of the upper bolts into the block and finger tighten them until they are snug to the pump. Do not overdo this. Reaching under the pump, do the same with two of the bottom bolts. If you were able to snug these up to the pump, you should be able to release the pump and insert the remaining bolts.
Tighten the bolts firmly without breaking them.
You need the water pump solidly attached to the engine block. This is not the time to prove that you have super human strength. When the bolts are tight, you are done with the water pump. It is time to begin putting all of the items back onto the car that you removed to reach the water pump. Start with the hoses and work your way back to the first piece and the belts.
Refill you cooling system with coolant.
Add back enough coolant to refill your system completely. If your car requires bleeding the air out of the system at this point, go ahead and get it taken care of at this point. When everything is complete, start your car and let it run until it reaches operating temperature. After it is warm and there is pressure in your cooling system, check for leaks around the water pump gasket. You may want to take the car out for a short drive of a few miles to make sure that all of the air is out of your system. If it does not overheat and the heater works, it should be good to go.
