+2 - lisle funnel is the way to go!

I honestly cringed when I saw the photo with the cap off while the car was under temp. Looked perfectly normal for a coolant system that needs to be burped. Lisle funnel will allow you to do that safely and easily.

 

I burped and filled it and took it to the auto parts store. Temp hit 240 and jumped promptly back down, air pockets I'm assuming. As I'm pulling in the gauge spikes to H and I see steam from the hook, the top hose to the AST popped off, what would cause that?

 

Yes it sounds like you have air in the system. Can't pressurize a system with air in it.

 

Well, I picked up a lisle funnel from advance. To make matters worse, none of the damn radiator caps fit. None. I managed to get the smallest one to loosely fit by bending the lip out with plyers, but filing the funnel, it backs up and leaks from the cap. Any suggestions on what to do there? car has blew that damn AST hose off three times.

Also, now it wont freaking start. Click. Click. Click. I tried taking two tiny gauges of wire and jumpering the two terminals on the plug for the security relay, nothing. Same thing.

I wonder if the AST spraying out of that overflow line got on the fuses/relays. I pulled them and made sure they were dry, still, nothing. Car clicks but will not start.


Anyone have any solution as to what I do about the lisle funnel/cap not fitting right, and the clicking but not starting?

Today has been an absolute day from hell.

 

Sounds like a hellish day for sure

Yeah, the Lisle doesn't necessarily fit well iirc but it's been ages since I used mine. YMMV of course. The other trick is to detach the coolant hose going to the throttle body and filling until it starts to come out of that hose. These days, I just generally assume it's going to take a few days for the air to bleed out and just take it for a short drive to get the thermostat open, drive home, cool off, top it off rinse/repeat 5-6 times.

Blowing the AST hose is odd. is it stock? aftermarket? what kind of hose clamp?

Check voltage at the battery when car is off and again when running to make sure your alternator is charging the battery and your battery can hold a charge.

 

^ +1 on removing the TB line, that plus the Lisle funnel will get you very close to air free. If you have the Lisle 24680 kit then you should have the right cap, I have the older version 24610 and the cap fits nice and tight. I let the car idle till the T-stat open and fans on, lots of air will rush up to the funnel when that happen. After that I remove the funnel and snap the radiator cap on with the car still running, then top off after the next few drives and usually require very very small amount.

What's going on with the filler neck? Looks like you have a 2-piece filler neck and the nipple removed and plugged? You have more picture of the engine bay to show where the AST is and what hose are use to connect everything?

 

For what it's worth, I had a very similar problem 2 years ago. I was driving around one day and noticed a burning smell. Temp gauge was near the top, and coolant had boiled out the overflow tank and onto the ground. It was a stuck thermostat. I don't know exactly how hot the car got since I only had the dash gauge, but it was pouring white smoke out the exhaust after that each time I started it. It was extremely obvious when my coolant seal let go (and yes I had good compression, too). If you aren't seeing that smoke, you may have gotten lucky this time and just need to burp your coolant system

 

I have the 24680 kit. None of them fit correctly, they are all too loose or the smallest one is too tight.

I use this on the filler neck, correct? How tight and snug should it be? It is normal to be loose enough that if I pour water into it, when it backs up, it leaks out the sides? I would assume not.

The filler neck I just assumed was factory, I haven't owned an FD in quite awhile.

The ast is factory. The hose that keeps blowing off is the tiny hose on the right side right below the pressure cap. I need to source a coupler for it, as it doesn't have one.


Asfor the car not starting...any ideas?

 

Yup you use it on the filler neck, yellow tube with rubber gasket goes inside the neck, and the metal cap goes on top to provide little pressure to seal it, then the funnel connects to the tube that stick out. There shouldn't be any leak, except a very small amount when you take the yellow tube out and replace it with a radiator cap.

That tiny hose goes to the reservoir, shouldn’t be any pressure there, that hose don’t need a clamp.

 

It leaked constantly. Those radiator caps did not fit for some reason. I have no idea why. I filled up three one gallon jugs about four times, it was just pouring out of the filler neck because the radiator cap wouldn't seal. I got fed up with it after awhile and just let it run and periodically added distilled water. Turns out the car ended up needing a jump, I assume that means the alternator is on its way out. As old as it is, I'm not surprised.

Anyone know where to source the zero psi filler neck cap? I can't seem to find one to save my life.

 

these are the lisle parts that worked for me...

 

^ Yup you need the B set, if you don’t have that set then I would return it.

The part number for the filler cap should be N3A115205A, if you have access to junkyard, you can find this cap in most 90s Mazda, I actually have a couple in the garage with all the old MX-6 parts.

 

That looked just like the set I had, But it did not fit, for some odd reason. I ended up returning it.

In the meantime I'm running two 13PSI caps on the system right now, since Advance didn't have a zero psi cap in their system for anything, which surprised me.

so I added as much distilled water as I could, and pressurized the system with the caps, added a hose clamp on that damn hose off the AST that blew off three times today, and let it run/idle for a solid fifteen minuts. Temps hit 187 at the highest with the AC fan on. I took it out onto a side street and did a few pulls up to 4k, and they hit 190 but came down.

Pulled in, and looked, there was some dripping from the overflow tank (minimal, however, still there.) Very thin puddle. This kind of worries me.

 

Post a pic of the AST and the hose that keeps blowing off. Have you pulled the AST and inspected it? One of the ports may be clogged.
If you have a blown coolant seal you should be seeing white smoke on a cold start, i'm with the other here on the poor bleed/burp.

 

It's also possible you pushed a ton of coolant to the overflow tank and it's too full right now. Check the dipstick on the overflow tank, if it's too full you'e going to need to drain it down. You'll need some sort of liquid pump to pump it out. It should be up to the full mark.

Dale

 

I would remove the fender liner and remove the tank if you need to drain it, it's really easy to get to with the wheel off.

 

Took it for a drive today, including stop and go traffic. After the thermostat opened, it started doing its usual thing, temp gauges would spike and quickly settle. OEM gauge would go to H, then drop after a few seconds. I'm assuming this means there is air still in the system. I checked under the car when I got gas, no dripping, and when I got back home, there was minimal dripping, maybe five or six drops from the coolant reservoir. It seemed the longer the car was being driven, the more often the temp spikes would happen.

Is it possible exhaust gasses are continuously entering the coolant system due to a bad coolant seal and causing this air pocket? I don't see any smoke on startup, but this is I think going on the third time now i'm letting it cool and adding more coolant. This morning though, it didnt take much, maybe a cup.

Also, after I got back, I let the car sit for about 10-15 minutes. I have one of those vented rad caps on the AST. I lifted the tab up, and immediately I heard gurgling/bubbling, and water started pouring out of the overflow..is this normal?

 

I chased a similar issue my first year owning my FD, and I was just as paranoid. It ended up being a small pinhole leak in a hose behind my alternator which let air into the cooling system. It took me several heat cycles with a lisle funnel to finally purge it out.

Have you tried using a coolant system pressure tester? I only found my leak after using one.

 

You should take the car to Rotorsports in Kannapolis, and let them straighten it out for you. But it still sounds like you need a burp. No white smoke means your seals are probably OK.

 

Normally I do my own work, or for internal engine stuff I take my cars to Pettit. But now that I haven't lived in FL for a few years, they are a bit far. Charlotte is considerably closer, though. I suppose it wouldn't hurt to have them do a look over of the car. I found a tiny pinhole sized leak in the system that was hissing and bubbling, the plastic part of the filler neck. Put some JBWeld in place and it seemed to have stopped. car probably took a few cups of coolant, I let it run and warm up, and this time I held the idle at 3,000~ for a solid five minutes, at least. Highest the temps got to was 206, and came down steadily after I let off.

I noticed when i turn the ac fan off the idle INCREASES, shouldn't it be the other way around? No coolant puked on the ground this time. Also, pictures of the AST hose I clamped, and the leak spot I patched with JB Weld, it was very tiny but enough for bubbles to foam their way out.

 

Wow
That looks like an OEM intercooler coupler. Surprised it hasn't crumbled apart after all these years like they did on my first FD many many moons ago

Yes, idle should decrease when the a/c and/or fan stop running or when you turn your lights off (electrical load).

You can get a replacement plastic part for the filler neck (and OEM parts in general) from Ray Crowe. He give us discounts on OEM parts and has 2 FDs.

Some links from the FAQ for you:
https://www.rx7club.com/3rd-generati...thread-571088/
https://www.rx7club.com/2nd-generati...ts-pic-853811/
https://www.rx7club.com/3rd-generati...ubbles-342309/

 

You have a pressure cap on the filler neck, but it should be a hard cap. I guess it doesn't hurt anything.

 

I had the regular zero psi cap, but lost it (long story.) After doing some research, I've read that people have ran a 13psi cap there fine as long as the AST is 13 psi as well. I need to source the zero psi filler cap to replace it, though.

I'm curious as to why the idle would increase a few hundred rpm when turning the ac fan off? Of course, the car idles at 1500 rpm normally and sometimes surges. It hasn't been driven very much, at all before I bought it. Believe it was from an estate sale at one point. I probably have to calibrate the TPS and whatnot. But why would the idle increase turning the ac fan off? that is just weird. Maybe something with the ISC/TPS?

Wonder if that tiny pinprick hole in the filler plastic piece had anything to do with the coolant system? I have a feeling though that I'm going to see temp spikes when I drive it again, though. Thats where it always seems to happen.

 

It should idle around 750rpm without surging. The AC circuit kicks on the idle speed control, and the computer tries to compensate for the extra load by increasing idle.

 

Yeah, that's how I've always understood it to work, but turning my ac off made the idle increase.