does the RX8 have an AST tank????
 

anyone know?

matter of fact...i think it does and i do think its plastic...lemme look through my pics and i'll dig up one!

-Zach

there ya go. That thing in the red square deals with coolant. and it is white plastic.

That looks like the over flow tank.

Yeh, does look like an overflow tank, but the only thing that doesn't jive is that it's got a cap that's unlike what you'd normally see on an overflow tank, right?

Gotta dump all that underhood plastic so we can see the guts.

I've seen larger caps on overflow tanks before. Perhaps that is a pressure cap and the tank is acually a reservoir like on a Fiat X1/9.

It's a pressurized expansion tank, that functions as an ast, a fill neck, and a pressure accumulator by way of the head of air that resides in the top halft of the tank.

As coolant heats up an expands during warm-up, the air is compressed in the tank. once cap relief point is exceeded, some air vents out that hose below the cap.

Most modern cars now use this concept (saab used it in 1980). It helps to keep system pressure at the cap relief point, so you don't get ever have a combo of sudden high load and low coolant pressure, which could allow brief, excessive local boiling.

and i guess since its mounted farther away from the engine than in FD's that it doesnt run the risk of cracking due to heat???

Also the hose connects is right at the cap (AST like), usualy the overflow tanks hose connection is on the bottom.