Well my AST recently exploded, so I made a venture the local junk yard to find a 86-88 FC filler neck top with the overflow. I did not find any RX-7's, however, all of the 80's 300ZXs have the same thing the FC's do, and the Z's are very easy to come by (there were about 5 at this junkyard). Anyway, I eliminated the AST and the car has never run cooler. I run at about 185 driving temps (90++ degree weather) and at idle for long periods of time I get a little over 200. I've got the Greddy FMIC too. It was a bit harder to get al of the air out, but now that it is out, she runs like a champ. I'm very very glad I removed the AST and would highly recomend it to anyone debating it right now. Just my $.02
Evan

 

The stock AST does not make the engine run hotter. You likely had a pressure loss that was fixed when you eliminated the ast.

 

and a FMIC does not make your car run cooler either lol

 

I believe he was saying his temperatures are reasonable EVEN THOUGH he has an FMIC.

Read the post again.

Always advisable, since getting that foot out of your mouth is such a pain.

 

Thank you kashent.

 

The AST might allow some hot water to bypass the radiator since it is connected to both the thermostat housing and bottom of the radiator.

 

There's a bit of a difference in flow rates between the large radiator hoses and the small hoses that run to the AST...

 

ive been running with out an ast for a couple years now. i didnt notice anything different when i did switch over. but 185f is kind of hard to believe in 90+ weather. what speed is this at? are you on a flat straight? going downhill? uphill? radiator fans on all the time?

 

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