How to Replace the Water Pump in a Nissan Pathfinderby Contributor; Updated November 07, 2017
How to Replace the Water Pump in a Nissan Pathfinder. The water pump is the heart of the Nissan Pathfinder's cooling system, circulating the coolant. A faulty water pump can cause some serious damage to the engine of your Nissan Pathfinder. To prolong the life of your engine, make sure to change out a bad water pump.
Remove the Old Water Pump
Place a drain pan underneath the radiator. When the engine is cool, drain the cooling system from the radiator into the pan.
Take of the undercover and the suspension member stay.
Un-install the radiator shrouds, the cooling fan and the drive belts.
Take the water drain plug out of the engine, which is on the side of the cylinder block where the water pump is located.
Pull off the chain tensioner cover as well as the water pump cover.
Push the timing chain tensioner sleeve up and put a stopper pin in it to keep it from slipping. Take out the chain tensioner assembly.
Loosen and remove the water pump mounting bolts and turn the crankshaft pulley in a backward motion until it rotates 20 degrees, which will secure the area between the timing chain and water pump.
Add 2 M8 bolts to the water pump fixing bolt holes. Tighten them by hand, alternating turning a half turn each at a time unit they reach the timing chain rear case. Doing it this way will prevent damage to the timing chain rear case.
Remove the water pump.
Install the New Water Pump
Put some engine oil along with some antifreeze on the o-rings and install the new pump with the new o-rings.
Clean all mounting surfaces on the water pump cover, chain tensioner and the front cover matting surface and then install these components.
Put a bead of liquid gasket onto the matting surface on the water pump cover and the chain tensioner.
Turn the crankshaft pulley back to its starting position (20 degrees forward).
Apply some engine oil to the timing chain tensioner and the oil hole and install the timing chain tensioner. Then remove the stopper pin.
Reattach and install all the remaining components in reverse order in which they were removed.
Start the car and check for leaks when the engine reaches normal operating temperature.
Loud noises coming from the cooling system in your Nissan Pathfinder could be a sign that your water pump needs replacing. A leak in the coolant may also be an indicator. Disconnecting the negative battery cable may reset the on-board computer system or parts of the computer system, so be aware that you may have to reset certain settings.
Be careful not to damage the o-rings by scraping the cylinder block when installing the pump. Never attempt to drain the radiator when the engine in your Nissan Pathfinder is hot. The steam and the hot coolant within the radiator can cause serious burns. Never leave antifreeze open or in puddles. Cats and dogs are attracted to the ethylene glycol in the antifreeze and if they drink it, it can be fatal.