How to Replace the Water Pump
By Doug Gentges
I replaced my water pump when it failed at the shaft seals. It
developed a slow leak for a couple of weeks before it got to the point where it was
un-drivable (my 7 is my only car). I think mine and most of the water pump failures on 3rd
gens are caused by over tightening of the belts. If you are replacing yours, forget about
the dealer, they get around $300 for the pump. I ordered the pump from Mazdatrix for
around $140 including overnight shipping. Replacing the pump is relatively simple
(its not much more difficult than replacing the plug wires). The pump is above the
radiator, and if yours is seriously leaking, there is probably no reason to drain the
radiator before changing the pump. If you dont have a leak, it may be necessary to
drain a little bit of coolant out before you remove the pump.
You need to remove the air box and all of the intake ducting up to
but not including the throttle body (you can leave the intercooler in), and take off the
Remove the bracket that tensions the alternator (there is a bolt
that is kind of under and behind the power steering pump. You will also need to take out
the alternator tensioning bolts.
There are three small bolts, four nuts, and one long bolt that hold
the pump to the engine block. You will probably need to remove the pulley from the water
pump while it is still in the car to access a couple of the bolts.
Scrape the old gasket, put on a new one, and re-install everything
in reverse order. And this time dont tighten the belts quite so much (use a belt
There is a kit that replaces the front water pump seal and the pump
mechanism, not the whole housing. Comes with the lower radiator hose, pump,
gasket, and coolant sensor. The Mazda parts person seemed upset that I knew
about such a thing without them having diagnosed a warranty repair.
Part No N3Z1-15-S20