AST: Eliminate or Replace??
 

What are the advantages of replacing the OEM AST with an aluminum one over bypassing it and taking it out. For a hundred bucks cheaper than the Pettit Aluminum AST, M2 has the bypass kit. Is there any reason I shouldn't just go with that?

I read somewhere that it's not really good to remove it since you can get air bubbles into your coolant system. I think I read it on the Robinette site in one of the notes I'm not sure

If you do a search, you'll see a LOT of debates on this. Basically, no one can really say you do or don't need it. It just depends on what you want..

Me? I figured that Mazda thought it was important enough to include it, so I upgraded mine.

I'll take the extra pint of coolant an AST offers. Expensive pint too.

After driving, I ALWAYS hear air escaping from the AST and my coolant system was just flushed and filled (and "burped" properly). I just don't see the reasoning behind removing it. People say "I've been driving with it removed for three years and I haven't had any problems." But most of these people put less than 10k miles a year on their car. So, the car has made it for 30k with the AST removed. Will it last 50k? 75k? Who knows. Maybe the coolant seals will crap out at 50k when they would have lasted 70k. I say pay the $150 for the damn aluminum AST and not ever worry about it again.

I eliminated the AST with no difference noted in cooling at all...of course I'm one of those who put less than 10k on the car a year.

I'm switching back to AST this summer because I do think it helps, if at all, to have an extra pint of coolant.

The common reasoning is that masda put i on their for a reason...

I agree exactly.

Ok I dont drive me car's much...I've had it on 2 FD's....for over 3 years total time...had the pettit tank for a couple years also....didn't notice any difference...

Currently I'm running eliminated for over 2 years... But I am not a fan on the idea that just because mazda put it there..there must be a reason...that is not logical !

come on...it's plastic...should be metal...there is are alot of things mazda does right and wrong...

I got the pettit tank, thought it was a good idea at the time I guess.

http://www.eframes.com/ef-cgi/S/Shei...8150search.JPG this topic...

if i were you i would replace it.

1FAST7

There is a good thread on this in the 3rd gen archive I believe.

Yea, but it's as divided as the 2mm vs 3mm seals and the Synthetic vs Non-Synthetic discussions. :)

Replace it. The more coolant capacity you have the cooler your car can run. Plus it makes it a pain in the butt to fill the radiator without it.

I went with the pettit. I like it.

Alright, that settles that. I'll fork out the 150 and get it. Thanks much to everybody for the feedback

For me, anything that makes my car special is worth having (based on OEM design, no fuzzy dice jokes please). And if you're going to keep it, might as well make it last. That's why I mad 30 of them for other folks around here.

Any chance ur gonna make more?

I installed the petiit ast and it added 50 horse power to the dyno run. get it.

J.O. Kerman

The ast makes the system more forgiving for small amounts of air/gas intrusion while running or during coolant change. If air intrusion exists, it collects at the filler cap, and is pushed out thru the ast at next cold start. The stock ast has a .085" orifice to restrict flow. Not much air is likely to collect in oem ast while hot running, since the orifice keeps flow very low so the small oem radiator is not bypassed.

I have no ast. No bypass hose ... plugged the ports to create 'mini ast', per my notes at cirian's/robinette's sites. The engine is young, and I frequently inspect level cold. It stays at the very top of the filler neck. An ast would make the system more tolerant if air intrusion occurs, as in old engines. But, a minor negative ... it also introduces more places for a leak to occur, as in xtra cap, 2 xtra hoses, and ast itself.

It's possible. I would need to get at least 10 people interested to make it worth the work. I'm not sure that there all that many people who are interested anymore. I've only seen a couple AST post in the past few months.
I'll think about it. I enjoy making them, so that's not an issue.

So what makes you think that this or any other thread on this subject will be different? ;) Everyone has an opinion. I say do whatever you feel comfortable with. Its your car and your $$$.

spooledUP7, just count me in for one if you ever do.

I also need one! How much a piece for a group buy of 10?

Yep, that's why I had posted: