Trinityevo13

iTrader: (1)

Hi all,

I recently converted to single, v-mount setup and deleted my AST. Ran the Banzai filler neck and have the single hose running to the Coolant bottle.

Here is the issue I am having. I bled the coolant multiple times using the Spill Free Funnel. I notice after driving for a while coolant is coming up thru the coolant bottle (small hole on top of the coolant bottle). I bled the system again and the fluid coming out of the bottle is less than before. Do I have an issue or the system just needs to be bled some more? Any suggestions on best way to bleed the system? I have done multiple 10 min sessions, idle, revving it, fans cycling on and off. Or do I need to find a way to remount my AST?

Cheers

DaleClark

iTrader: (55)

OK let's make sure you did the job right.

The AST has 3 hoses going to it -

1 - the overflow tank
2 - the bottom or the radiator
3 - the thermostat housing

The nipples for hoses 2 and 3 need to be either blocked off or joined together. Easiest is typically just to take one of those 2 hoses and attach the 2 nipples together.

Hose 1 will go to the new filler neck on top of the thermostat housing where the radiator cap attaches.

Hose 1 is a zero pressure hose. As the coolant warms up, extra coolant gets pushed out of this hose to the overflow tank. As the system cools, it sucks coolant from the tank back into the system.

If that hose has any air holes (a pinhole leak, not a tight seal on one end, etc.) it can't suck the coolant back into the system, it just sucks air. So it keeps pushing coolant into the overflow tank until it barfs out the top.

Also the overflow tank needs to be filled to the fill line on the dip stick that goes down into the tank. If it's too full you will have a similar problem.

Dale

Trinityevo13

iTrader: (1)

Thanks as always for the feedback Dale, appreciate it.

Hose 2 - no provision on the aftermarket rad for a hose, so its "blocked off"
Hose 3 - currently blocked off - no leaks

I did check the coolant bottle and it was a tad bit above the "Full" mark. I will remove the excess and see if that helps. I will also check the lines again for any leaks, didn't see anything on the hose from filler to coolant bottle. I could replace that hose also.

Side note: When the car is warm and I shut it off, you can definitely hear what i assume is air going thru the rad hoses, also I can feel air moving thru the hose itself, based on the vibrations felt on the hose. Is this normal?

Cheers

DaleClark

iTrader: (55)

Sounds like you may still have some air in the system.

You want to do this -

- Hook up the funnel
- Put some coolant in the funnel so it's about 1/3rd full.
- Start the car and let it idle
- Let it get all the way up to temperature, around 80 deg. C, so the thermostat is open. Once the thermostat opens you may start seeing more hot coolant coming up into the funnel.
- Let it run for another 5 minutes or so after the thermostat opens. Top up coolant as needed.
- Shut the car down, LEAVE THE FUNNEL ON, and let the car cool down and suck that coolant in the funnel in if it needs it.
- Let it cool ALL the way down before removing the funnel, top off the fill neck if necessary.

It can also help to have the front up on jack stands. Some V-mounts can be hard to get all the air out, air can get trapped up at the top of the radiator. While the car is running with the funnel on it can help to squeeze the radiator hoses a bunch to help force and move coolant through.

If you have air bubbles, the car will have a hot spot in the system, will boil and will shove a lot of coolant into the overflow tank as that air bubble expands to steam and raises the pressure. That could be what happened.

Dale

Trinityevo13

iTrader: (1)

Thanks a lot Dale, I will give this a try on the weekend and report back. I like the idea of having the front up in the air, i think that would help.

Cheers

Banzai-Racing

iTrader: (11)

You are using a pressure cap on the filler neck and not the original flat cap?

Trinityevo13

iTrader: (1)

Hey Banzai,
I have the OEM flat cap on the Banzai Filler Neck

Cheers

Sgtblue

iTrader: (16)

The Banzai neck is now functioning as you AST. You need the spring cap on it. Personally I recommend the OEM .9 bar version.
Also check the level of your overflow reservoir. Your probably way over-full there now.

Trinityevo13

iTrader: (1)

Thanks Sgtblue, will take a look at some cap options after I try to bleed the system again based on Dale Clark's recommendations.
I will double check the overflow reservoir as well and adjust accordingly.

Cheers

Trinityevo13

iTrader: (1)

Also, any link to the OEM .9 bar cap? Based on a quick google search it looks very similar to what I have on the car now. Just want to be sure.

Cheers

DaleClark

iTrader: (55)

If you still have your old AST just take the cap off of it.

Mazda has the radiator caps, just get a stock one and you'll be fine.

Yeah if you used the flat cap there's your problem, hands down end of story.

Dale

Trinityevo13

iTrader: (1)

Thanks Dale, I should have the old AST somewhere with the circular cap on it and I know I changed the caps to new ones. I had an aftermarket AST but I am sure that cap wouldnt work lol. I just hope it fits the Banzai filler neck. Will try it later and see

Cheers

Trinityevo13

iTrader: (1)

Found the old AST with the circular spring cap (0.9 bar). I ran out to the car and swapped the caps real quick. Its a bit of a tight fit on the Banzai Filler but it seems to fit. The circular design doesn't help to get it tightened like the other cap with the tabs. I will try to start the car/ drive this week and report back.

Question for you @DaleClark .....should i still go ahead and bleed the system again as you suggested or watch how it reacts to this cap first, with the correct fluid level in the overflow reservoir?

Cheers

DaleClark

iTrader: (55)

Probably worth a bleed since you got air in the system with the flat cap being on there.

You can get the radiator cap for the FC that has the "wings" on the side that make it easier to install and remove. I think you can also get the RX-8 radiator cap.

Dale

Banzai-Racing

iTrader: (11)

Caps are on the same page as the filler neck Air Separation Tank (AST) (93+ RX-7)

Trinityevo13

iTrader: (1)

Thanks Dale, I will bleed again on the weekend and report back. Will give this cap a try and change if necessary

Cheers

Trinityevo13

iTrader: (1)

Great! Thanks Banzai, i will take a look. Appreciate it

Cheers

Trinityevo13

iTrader: (1)

Hey all,

Update:

Bled the coolant some more as Dale suggested. Front jacked up on stands etc …. Saw a few bubbles in the funnel but nothing too crazy. Also squeezed the hoses to help. After the idle, allowed the car to cool down completely and it took a fair bit of coolant so I hope that’s the coolant replacing the air!


Coolant reservoir was at the Full mark and the water neck topped off. Went for a drive, few miles, and didn’t see any fluid pushing from the reservoir when I got back home. So that’s a good sign. This is of course with the new rad cap installed (.9 bar).

I did notice when the car was warm I could hear air bubbles in the coolant hoses, not sure if this is normal without the AST? Also the fluid in the coolant reservoir was a bit past the full mark, I assume normal as well when the car is warm? I will recheck the level on the reservoir when the car is completely cold tomorrow and see the reading.

Thanks for all the help!

cheers

DaleClark

iTrader: (55)

The overflow tank level should be checked when cold. The level will come up and go down as the car heats and cools.

It's worth checking the coolant level a few times over the next few drive cycles and topping up as necessary. With your setup it may be a bit of work to get all the air out.

It generally sounds like you've got it under control, though, and the car is now safely drivable which is good.

Dale

Trinityevo13

iTrader: (1)

Thanks Dale. Went for another drive this morning and was more of a “spirited” drive if you will and came back home, no coolant out the reservoir. Cap is holding securely

Checked the coolant reservoir level when it was cold before I went for a drive and it was just about at the full mark.

I will be monitoring it as I continue to drive the car. Thanks again to everyone for your help. Dale Clark as always your feedback and advice is always appreciated.

PS… I ordered the FC .9 bar cap lol! The circular one is a pain to remove and tighten when you need to check the water neck.

Cheers

Trinityevo13

iTrader: (1)

Hi all,

Update on this issue. Went for a more "spirited" drive this weekend and came back and saw where coolant was on the floor, coming from the coolant reservoir

I did note however, that the coolant reservoir was about 3 bars above the full mark prior to driving. I am hoping this is just the excess coming out. Will keep checking the levels as I continue to drive the car. Temps are all normal and the fans work as they should. Just wanted to share an update in case anyone has any other theories on what's the issue here.

Cheers

Sgtblue

iTrader: (16)

Either pull the wheel-liner to access the overflow reservoir to get it down the the full (cold) level or use a bulb syringe and a length of tubing to do the same. Make sure your (OEM?) spring-cap is tight and check to make sure the hose from the filler neck to the overflow reservoir isn’t kinked or pinched…it’s a thin wall hose and susceptible.
With the level correct in the overflow and the system full at the filler neck, bring the engine up to full operating temp. Shut it off, park it on a level surface, do NOT open the spring cap while letting the engine cool completely overnight.
Check the overflow reservoir level. If it’s still overflowing I would suspect a leak somewhere in the system…a hose, gasket…something that’s bleeding off the natural vacuum that should draw coolant back out of the overflow as the engine cools. And a pressure test of the system would be in my future.

Banzai-Racing

iTrader: (11)

Or the seal on the old used cap isn’t any good

Trinityevo13

iTrader: (1)

Thanks Sgtblue, the cap seems to be in good working order. I have the FC style cap on order which makes it easier to open and close. @Banzai the cap seal looks to be in good shape. Once I get the other cap will swap it out and see if it makes a difference.

Will check the hose again to ensure no leaks. When the car idles and isn’t driven no coolant overflows from the reservoir. Only if the car is driven and even then it only happened this weekend for the first time in about 3 or 4 drives.

I will give your suggestion a try and recheck the coolant reservoir again.

Thought I had this one beat lol, guess not…

Cheers

Trinityevo13

iTrader: (1)

Hi all,

FULLY BAFFLED ON THIS ONE !

The car has been sitting for about 4 days, no driving, no starts, zero.

Checked the coolant reservoir and it was way past the Full mark. I said ok, I would remove some coolant from the reservoir. Before I did that, I decided I would check the water neck. While removing the cap, coolant literally rockets out of the filler. I mean fully soaking me, the engine bay, even things beside the car!!! now I have never seen ANY car do this before.

After spending close to an hour cleaning up coolant, I removed the fluid from the reservoir and topped up as necessary. Made sure it was right at the full mark. Coolant was at the filler neck. I thought all is well. Started the car and fans come in and out as they should. As soon as I am about to drive on the road the “Add Coolant” light comes on and the loud buzzer. I go back, let it cool and top up again at the filler neck. Drive out again, same thing happens!

What am I missing!! Or is something wrong - cap??, too much coolant?? There is zero smoke from the exhaust…car idles fine as it should. Oil pressure is good ….. baffled!!!!

Any recommendations or theories out there??

Cheers