Should I keep the AST?
 

What's the AST for? What' the advantage to keep it? and what's the advantage to take it out all together?

Now I see how you got 2452 posts!!

:fruit::fruit::fruit::fruit::fruit::fruit::fruit:

The AST (Air Separation tank) was included on the 3rd gen to remove air bubbles from the coolant flow thru the system. It traps the air that would otherwise impede and "hiccup" the steady coolant flow. Can't be that good on the water pump either. I was going to eliminate my AST, but if the coolant system isn't "burped" correctly after eliminating it, I'll get air in it. Buying an aluminum Pettit AST soon and keep it the way Mazda designed it. They must've had a good reason for using one.
Removing it seems to cause no ill effects, but whatever you decide, get rid of the plastic POS AST that came with the car before it splits and you end up ice-skating into a curb.

Hey NEO if you want I will sell you my Aluminum AST if you want 2 months old, but you should definately get rid of that plastic crap.

Is it Petti? How much? and help me to put it on?