Hey guys, could use some help to get my seven back on the road (phoenix area).

I snapped the corner off the waterpump housing while replacing the thermostat and I'm not seeing any direct replacements on ebay at the moment.

So my question is what other models will work as a replacement? For example can I use an S5 waterpump housing (89-91?) or from a turbo model?

I'm looking at a pic of an S5 and I'm guessing I would at least need the connector to the rad hose because there are 3 bolts instead of two. Link:

http://www.ebay.com/itm/mazda-rx-7-rx7-engine-13b-89-91-non-turbo-water-pump-w-aluminum-housing-/201154062975?hash=item2ed5b76a7f&vxp=mtr

 

there are basically 5 water pump housings.

86-88 NA
86-88 turbo, the turbo adds a little coolant nipple for the turbo.

89-91 m/t, as you've noticed it takes a different thermostat neck. it also takes a different water pump, and pulley, thermostat. it should actually go right in, but you may need the S5 radiator hoses, as they are different.
89-91 turbo, same as the m/t, but adds a fan switch, and a nipple for the turbo coolant.
89-91 a/t. has the extra fan switch, but is otherwise the same as the m/t

 

Thanks for the comprehensive response!

So, will any of those differences make installation difficult? I can't tell if an extra coolant nipple or fan switch (electric?will no longer be connected to drive?) or pulley difference will be an issue and therefore if I should avoid buying certain models as a replacement.

If the S5 has different sized hoses, is that just the upper and lower rad hoses?

 

The water pumps are different between s4 and s5, the pulleys for the water pump are different, because the center stud on the pump to align the pulley and mechanical fan is larger on the S5 setup. So if youre going to use a S4 pulley and fan youre going to have to modify or use the other s5 parts to go with. The t-stat neck is also different so you'll need one to go with the S5 one as well.

 

That sounds like a headache, what about an S4 Turbo waterpump housing, would that be a direct drop in? Or will the dreaded nipple mess things up?

 

S4 tii housing will use a S4 pump. You'll have to plug the extra coolant port on the bottom of the housing by the low rad hose thats used for the turbo coolant return, but thats not a big issue.

 

S4 pump has less a 7 bolt pattern on the pump compared to 8 on the S5,so you really can't interchange the pumps on the enginw without using the appropriate housing.
You can use the S4 TII housing on the N/A pump though.
Some guys actually like using it as it gives you the alternative to "boost that baby" if you desire to later!It has the nipple for the turbo coolant return line.

 

The turbo housing can come in handy on a NA as well because you could use the "turbo drain" as a return for the heater core.
This would open up radiator options as you would no longer need the RX7-specific return bung on the lower rad fitting.

 

S4 N/A water pump housings are very easy to find, and dirt cheap.

 

Well thanks for the help everyone, right now I can't find any used housings for sale. If anyone knows where I might find one I would really appreciate it!

 

Have you checked Rockauto.com yet?

 

I just did now. They only have the waterpump alone for sale, not the housing near the t-stat neck where I snapped the corner off.

 

ahem..
2nd Generation RX-7 (1986-1992) Parts - RX7Club.com