Water Pump and Pulley Install
Note: Although this tech story has been performed on a ahem… Chevrolet engine, the tips and techniques described can work on any brand.
Time: 2 hours
Tools: standard socket set, standard wrenches, gasket scraper, long screwdriver or pry bar
Cost: approximately $50-$150 for the pump, $25-$50 for the pulley
Tinware: new performance water pump and gaskets (supplied), deep-groove water pump pulley (optional).
Tip: never reuse old coolant. Over time it can chemically breakdown and actually harm and attack the internals of your cooling system.
Performance gains: a lighter (aluminum), more reliable, higher-flowing cooling system
Along with the radiator, the water pump serves as the focal point of the cooling system.
Without its vital contribution, there would be no water/coolant flow through the engine. And we all know what that means– total meltdown! In fact, the water pump acts as the instigator in the system, immediately initiating the flow of coolant when the motor is fired up. The impeller inside the pump draws in coolant via the lower radiator hose and pushes it through two passages into the engine block. Once inside the block, the coolant circulates around each of the cylinders on both sides, picking up heat along the way. Working in a front to rear fashion, it then moves upstairs into the cylinder heads where it continues to cool the valve pockets and guides, exhaust ports, and combustion chambers. The intake manifold and its thermostat is next. Depending on the operating temperature of the motor, the thermostat will allow the coolant to re-enter the radiator to be cooled and re-circulated once again through the system.
Assuming everything is in perfect working order, that all sounds fine and dandy. However, over time, this system and its hard working components slowly deteriorate and fall victims to negligence. It’s amazing they last as long as they do. When it comes to water pumps in particular, the most common failure is typically the impeller. Although your stock water pump may appear to be fine and show no signs of leakage, the impeller could be in serious trouble and unable to pump the required volume of coolant. Why? Slowly but surely, coolant in the system becomes acidic and will eat pretty much any form of metal in its path, including impeller blades!
Whether it’s a daily driver or a drag strip demon, this is ultimately unacceptable. And seeing how easy it is to swap out, it’s really a no-brainer. The water pump and its counterparts are all readily accessible at the front of the motor and require minimal effort to upgrade (just a small wad of greenbacks).
The first order of business is to drain the cooling system. Using either the radiator drain plug or the lower hose, carefully empty the old coolant into a large container and dispose of properly- do not reuse it! Spend the extra ten bucks and refill the system with clean fluid. When the system is finally empty, go ahead and remove the radiator hoses to allow for better access to the fan and water pump.
Next up are the water pump accessories. This may vary depending on your particular application and equipped options. Starting with the fan and working back, remove all necessary brackets and attaching hardware from the pump. If this is your first time, keep track of what goes where to avoid any confusion or mix-ups later.
Held in place by four 3/8” bolts, the water pump can now be eliminated. Even after the bolts are out, you may need to smack it a couple times with a rubber mallet to break the bond. Take a look at the passages in your old pump. This gunk has been free flowing throughout your motor for years!
Before simply slapping a gasket down and installing the new pump, take the time and thoroughly clean the mating surface (see photo 1). If you’re unable to remove the old material with a scraper, stuff a rag in the ports and try a small diameter wire wheel attachment. Often overlooked, this is a very crucial step for a long lasting seal.
Using a small amount of gasket sealer, apply the new gaskets on the block and install the pump. Let the sealer briefly “set-up” prior to installation to avoid the gaskets from slipping out of place. As seen in photo 2, tighten the water pump mounting bolts slowly and evenly. Remember, aluminum has a higher thermal expansion rate than cast iron so be careful not to over tighten. It’s always best to follow the manufacturer’s torque specs whenever possible. In addition to the water pump, we also decided to purchase an aftermarket aluminum deep-groove pulley. These work great for positive belt retention in high performance motors, and they save weight. Every little bit counts!
The rest of the reassembly is straightforward- just reverse your steps to complete.