I got my new w/p with housing which is pre-assembled together. Manual says 'don't forget the shims where the studs don't have gasket'. Well, looks like I did not get the two shims.

Before I tear into this so I have all the parts, can my original shims on the car be reused? If not, anyone know the size?

I did search but only really found someone had a w/p crack in 1/2 without the shims.

 

I've reused them. each time.

They're pretty thin. I'd say 1-2mm.

 

Mazdatrix sells them.


There's a dude on here somewhere that didn't have the shims, and his waterpump exploded at 8000 rpms.

 

If you question the shims at all, get new ones from a dealership or from Mazdatrix. Don't screw around. Don't guess. Don't try to research it on the internet. Just buy the right part.

That being said, you should be able to reuse them. I'd trust a reused one over a "guess and check" part any day.

 

Are the shims S4 specific? I don't recall there being shims on my S5 and don't see a reference to any in my FSM.

 

S5 doesn't require shims

Thanksl for the info. I was just wondering about 'shims' and what that actually meant. My motorcycle had so called 'shims' that ended up being like a gasket with adhesive backing.

Since the s4 shims can be reused that's what I'll do. Thanks

 

Yes, they are S4 specific.

She S4 water pump housings were flat machined, so they needed shims to make up for the compressed thickness of the water pump gasket not being present on the two outside studs. Not using the shims places uneven tensions on the housing and the iron.

It'd be a pretty safe guess that a couple shims got left off and caused warranty issues, because on the S5's, the shim thickness was machined into the water pump housings.

On the S4's, you can also simply not use the gasket and apply a very thin layer of RTV silicone. However, the S5's must ALWAYS use a gasket.

To recap:
S4- if using a gasket, use the shims. No shims if only using RTV.
S5- Must use a gasket, must not use shims.