Replacing a water pump is fairly inexpensive. It's also necessary if you don't want to end up stranded anywhere. A mechanic may run you about $400 or you could save some money and do it yourself.
To replace a water pump you’ll first need to disconnect your battery, remove your serpentine belt and dislodge your water pump pulley. To remove the serpentine belt you’ll need to insert a ratchet bolt into the tensioner hole of your serpentine belt, which is located in the middle of the alternator pulley. It’ll be a square hole in the center. Using the ratchet bolt, push the tensioner to the right to give the belt some slack in order to slip it off.
The water pump pulley will require you to remove three bolts. These will be easy with your ratchet, but you’ll need to insert a screwdriver into the holes to keep the pulley from spinning. Once that’s over, you can disengage the water pump. You’ll need to take out seven 10mm bolts with a ratchet and socket.
These are aluminum, so be careful not to bust them. Have a catch basin ready to catch any coolant that spills out. Now you can remove the water pump. Remove any old residue from the gasket and spray some new sealant into the mounting area. Insert the new gasket and water pump and line it up with the mounting holes. Once in, give the bolts some torque to make sure they’re tight.
When placing the water pump pulley back on, you’re not required to give them torque, just tighten them. Finally, you’ll need to give the alternator pulley some slack by inserting your breaker and ratchet into the tensioner hole. Once enough slack is created, slip the belt back on and return the tensioner pulley to its normal position.