AST delete and filling system
 

Just curious if anyone has any tricks to filling the system with an ast delete and if anything is so different than with an AST. Topping off the system? Just pop the cap and top off?

This is with a Koyo Nflo if that makes a difference.
some say the Nflo is a huge pita because air can get trapped. Thanks for any help.

I just went through this with my FD, also a Koyo N-flow, no AST on a completely drained system, here's a few tips to make it less of a PITA

- If you don't have one already, get one of these Lisle funnel kits, they make burping the air out of the system so much easier and less messy. You can buy it on Amazon and just about everywhere else: https://www.lislecorp.com/specialty-...ree-funnel-606

- Before filling, don't forget to set the heater to max heat so coolant can flow into the heater core too.
- Go very slow when pouring the coolant in so the air can get out while you pour - you don't want the flow of liquid to block the flow of air out.
- Taking a break from pouring and giving the upper & lower rad hose a squeeze occasionally seems to help persuade the trapped air out a little quicker.

To finish the job, fire it up with the Lisle funnel still attached and with about 1/8 ~ 1/4 full of coolant in it. If the level drops as the car idles and warms up, just slowly add more coolant, always keeping the funnel 1/8 ~ 1/4 full. After reaching operating temps, shut the car off & let it cool down - the coolant level in the funnel may rise after you shut down, that's normal. Hopefully it won't overflow the funnel (that's why you want to keep the funnel no more than 1/4 full). As the engine cools, the level may drop again - just keep it topped off if it does. Repeat the process for another heat cycle or two if the level drops at the end and you have to add coolant to get it full.

Thanks. I really appreciate you taking the time.
Do you just pop the cap on filler neck and check level from time to time? Or do you just rely in overflow reservoir?

I ask this because I feel as if my coolant level isn't totally full.
When I shut my car down the coolant temp immediately goes down a few degrees until it starts to heat soak a bit. I always go back and run my fan for a min and restart to cool everything down. I usually do this 2x with the last being when I pull it into the garage. I run it until it is back to 82°c and the fans kick off.
I see no reason for the immediate drop in temp (let's say 5°c) if the coolant level isn't possibly going below sensor. I can not be more happy with my cooling system performance at the moment though. I am only boosting off wastegate (7psi ish) but in South FL temp I am not getting above 87c. This is with higher oil temps also which I just fixed.
I guess I should look how low the temp sensor is on this thing. I forgot.


I just popped the filler cap and it's full. Glad I have awhile before flushing!

Agree with the lisle funnel. And also make sure the overflow has coolant. Then check the engine coolant level when completely cold after the next couple heat cycles. I can usually get a few more oz. in it. I change coolant at least bi-annually and it really doesn’t take any longer than with the AST.
I ran the plastic FC piece on the filler neck for a few years without issue but Banzai’s billet neck won’t crack and has a better quality ‘O’ ring. It’s a nice piece and I run that now.
http://www.banzai-racing.com/store/93%2B_rx-7_AST.html


https://cimg8.ibsrv.net/gimg/www.rx7...b16b52d70d.png

Thanks you guys.

I'll pop the cap on a cold engine to check the coolant periodically. In theory, if the pressure cap and overflow tank plumbing is functioning properly, checking the level in the tank is good enough. But I prefer popping the cap on a cold engine for that extra peace of mind.

Thats what I had to do and took me a long time.. I shouldn't be messing with it any time son, cause I can't be wasting my Evans..:suspect:

Again, just for the record. You guys running a .9 bar? My engine builder put a 1.1 and I am thinking of changing it to a .9.

I run a .9 bar. I’ve never seen a need for higher. Yours may actually be a 1.3 bar.

I have a 1.1 and do not see a reason for anything higher. I will order an RE Amemiya cap, unless you know of something easier to obtain. Most of what I see is 1.1 or 1.3, but hard to find a .9?
Probably Mazda has o e that I just didn't see lol