Water Pump replacement - what's this job like?


Mazda5 the Anti-Van
I have an older thread about the smell of coolant. Well, changed the oil Saturday and since I had to remove the "skid plate" I saw where all this water has been going. I followed the dried water trail back to the pump, but from what I could see, it looks buried in there pretty well. Anyone do this job and can give me tips and suggestions?


Mazda5 the Anti-Van
Tried to get the water pump changed today. Might I suggest that if yours begins to fail, you sell the vehicle? I ordered the pump ages ago and when it arrived, I saw that the pump just literally just pops right into the block right behind the thermostat. No gasket, just an o-ring. Looks like a pretty thoughtful design. And I think it is, when the block is on a stand. In reality, the pump is DEAD CENTER against the frame. The pulley is about 4" and the top of it is about even with the top of the frame rail. There is about 1 1/4" between the pulley and the frame. Not enough to put a ratchet into to remove the pulley bolts. Box wrench was moving the pulley against the belt, so I decided to remove the pump and pull the pulley off outside the car. Started to remove the pump bolts with an 8mm box wrench. The pulley interferes. So I thought I could pull the pump out 3/8" to meet how far the bolts go, then remove the bolts more, pull the pump to meet that new distance, etc until the bolts are free. The O ring keeps it all nice and tight in there, so it wasn't budging. Used a screwdriver sized chisel got about 1/8" before I realized that the pump innards are deeper than 1 1/4" which is all the space you have, even if the pump pulley is removed. I fear jacking the motor up a good 4" will stress all the components that run btw the powertrain and the body - like exhaust, A/C lines, half-shafts. So I have an even GREATER fear that all of that has to come OUT just to do a $30 water pump that is completely external and readily accessible!
Did you try pressure testing the cooling system to double confirm where the coolant leak is coming from. I would want to be 110% sure it was the water pump.

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Mazda5 the Anti-Van
Since the belt is off, I really should pull the alternator and look back there to see exactly where the FL22 is weeping. I guess its possible its coming from the Tstat housing, and with how I don't like the idea of jacking the engine up 3", this would be a good call.

I know this is an old thread but thought I would give it a shot.
Where you ever able to replace your water pump? If so how did you do it?
I am in the same situation now with my 2008 Mazda 5. I got the water pump loose but not enough room to pull it out from the block.
Any advice would be greatly appreciated.

Thank You!

2010 Mazda 5 Sport
Ugh. Sounds like a job for a shop when the inevitable time comes.

I hate transverse engines.
12 Mazda5 Grand T
So, I finished replacing the water pump on the 2012 Mazda 5. Better than an Audi job, but still not great.

First, you will need to be resourceful with your brain and your tools to get that thing out. You'll likely need a long handle 8mm wrench. I also did the thermostat/housing and it was not easy, but got it done. You will eventually need to jack the engine about an inch up to get the pump past the frame rail.

I'm not a mechanic and this is only how I did it. Here goes!

First, drain the coolant from the driver side petcock of the radiator. Catch and recycle.

Remove coolant overflow tank.

If the serpentine belt is on, try to loosen the 3 pulley bolts (10mm) with a wrench while the belt tension is holding it. I already had my belt off for other reasons and still managed to get it off by putting the 10mm wrench on and using a bigger wrench to wedge the other two bolts so I could hold it. Get the pulley off now and clean it well on both sides.

The pump has 3 8mm bolts holding it to the block. Get these off however you can. I used a long handle 8mm wrench. Under the car you'll need the long wrench since a socket doesn't fit.

Now, to get the pump out you will need to pry and jiggle, and tap and pry. Go underneath and tap and pry, go on top and tap and pry; repeat. Eventually, it will pop off (and a little coolant), but you cant get it out just yet!

Remove the 2 17mm bolts holding the engine mount to the frame rail. Jack up the engine about 1 inch and you can wiggle the pump out of there now!

Installation is the reverse. RTV is not recommended on the new pump since the new O-ring will seal everything just fine. There is a reason the factory didn't use sealant!

Be VERY careful to not over tighten these little bolts. They go finger tight, and then not much more with a small wrench. Use light thread locker too. Don't strip the block threads! Sorry, I don't have torque specs, but it is amazing how very little torque are on these little 8mm bolts. Don't worry, the o-ring will seal, it's not a gasket situation here.

Using light thread locker, put the pulley bolts back on as tight as you like with your wrench. After the belt is back on, make sure they are tight again.

Install coolant tank.

Fill with new Mazda coolant (green).

Start it up and check for leaks. Watch and fill tank as the system purges air over the next 100 miles.
I did this about a year ago on a 2007. I do not remember anything unusual or difficult. It was the easiest water pump replacement I've done. After the pulley is off, you have to tilt the pump to get it to clear and out.