Deciding to step up to the Revolution/AutoStaff “Radiator Outlet Tank” cost almost 3 weeks of downtime. I had to order this part from RHDJapan in the midst of the water pump service. Unfortunately, this was the last piece of the puzzle and I wasn’t able to finish everything up until the part was in hand.

After waiting 2 weeks with no shipping update from RHDJapan (they first have to receive the part from the manufacturer), I opted to pull some strings just to ensure I could get the car operational again. I have little patience when it comes to these types of things, which probably alludes to how I powered through the single turbo conversion in a few months. It really bugs me to leave a job unfinished.

So I settled for second best, as it was better than nothing at all. A member on the RX7Club forums actually made a small run of a similar product, inspired by the original. These were sold out before I could grab one, but I chased another avenue and it turned out a buddy of mine bought one and never installed it. I explained my situation and he was generously willing to pass it on to me. As I said before, the community is an imperative resource.

Of course, the very next day after all this happens, I get an email from RHDJapan noting that my order was shipped. Miraculously, according to the tracking number, the Revolution part was already in San Francisco and waiting for customs. It actually shipped 2 days prior, but I got the tracking number too late… talk about complicating things.

Revolution made the outlet tank with a zero pressure, screw on cap. Meaning, it was simply a fancier replacement of the stock thermostat housing and, like stock, a separate Air Separator Tank (AST) was required. I wanted to integrate the AST directly, so I had the screw on filler chopped off and a new billet, radiator filler welded in its place (thanks FFTEC, again). This would allow me to run a pressurized 13psi cap, effectively obviating the need for a separate AST.

For comparison’s sake, here’s a side by side of the Revolution tank (left) versus the locally made copy (right).


The scalloped section on the bottom allowed for perfect clearance with the idler pulley.



The difference in quality is easily recognizable. Yes, the Revolution part is prohibitively expensive and a hassle, but you truly get a well-made product. The entire flange is billet and even the outlet for the radiator hose is billet.

I also took the opportunity to refresh the thermostat with a new OEM replacement. It seems as though Mazda changed the design and build of the thermostats. The later versions are simpler and the jiggle pin is moved inward near the center opening.

Left: Old; Right: New


Finally, here is the Revolution tank installed with a 90* 1/8″ NPT to 1/4″ barb for the overflow nipple.


I think it adds a nice touch to the engine bay! A vast improvement over the ungainly stock counterpart.

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