TailHappy

Well, I'm still wanting to deny that my coolant seals are bad. I was having sputtering startups with white smoke and empty filler necks, but I added Dike to the coolant and that had gone away. Then this morning I started the car and got the coolant buzzer right away again. Damn. AST and filler neck were totally empty and the overflow was overfilled.

So two questions. First, why doesn't it pull the coolant back from the overflow? Is it possible I have a leaky hose that's killing the vacuum that pulls the coolant back in? Or is this definitely seals?

Which leads to question two....Like I say, the car's running great, starts fine, no smoke. The coolant buzzer is the only symptom. How much life would you guess is left in the engine? I can deal with pouring coolant in once a week, but didn't know how quickly it'd deteriorate. I don't know whether to expect to have to sell my kidney next month or next year.....

Thanks

evot23

iTrader: (17)

Definitely check/replace all your hoses and perhaps change the coolant while you are at it.

What about your water pump...if that is failing that may account for coolant loss.

Otherwise, get the kidney ready....maybe some of your liver too.

Hope it all goes well for you.

TailHappy

Yeah, I flushed the system and put on a Pettit AST last weekend. Didn't seem to make any difference. Water pump was changed last year, and there's no leaks under the car. And I don't think I'm losing any coolant, it's just all going to the overflow and then it's never being pulled back into the system. Now I gotta tear in my beer.

DamonB

Sounds like the o-rings. For what is worth mine started leaking about 6 mos ago and I did the copper block weld treatment. It lasted about a week and then developed a very small leak. I repeated the treatment and everything has been fine since; and I drive the hell out of the car, about 2500 miles a month and races every other weekend.

The coolant gets pushed out from combustion gases leaking out and/or the coolant overheating and venting from the cap. The motor can't pull it all back in because either A) some of it is on the ground or B) some of it was released as steam or C) some of it went out the tailpipe.

As long as you are having trouble starting and are loosing coolant, you still have an internal leak.

kempo

iTrader: (2)

take your car to a radiator shop they should be able to test the cooling system for carbonmonoxide if the conbustion gases are going into your coolant.

Tom93R1

iTrader: (2)

Definately check the cap. I had the exact same problem with the overflow overflowing, empty AST and filler neck. Turned out that I had a pressure cap where I was supposed to have the non pressure relief cap and that didn't completely seal. When pressure built up it would seal but when the engine cooled and the coolant was supposed to be sucked back in the cap wouldn't hold a vaccuum and air would get into the system.

evot23

iTrader: (17)

So you are saying that the coolant filler neck is not supposed to have the pressure spring?

Eddie

evot23

iTrader: (17)

I eliminated my ast and replaced the stock filler cap with the one with a spring. Wrong of me?

TailHappy

That's (sort of) good to hear, DamonB. I autocross mine once a month, and hope to get a track day about as frequently. I'll be ok if this thing would just hold up a year or so.

Dropped it off at lunch to have a pressure/leak check done. Sputtered a little again when I started it, but didn't visibly smoke. Should find out this evening what the diagnosis is...

As far as the caps, good tip but I replaced both last month. And then the AST one just got changed again when I put the Pettit on.

evot23, when stock, you should have a pressure cap on the AST and a non-pressure cap on the filler neck. But if you eliminate the AST, I think you would want a pressure cap on the neck at the block so that you'll have some release for the pressure if it gets too high.

Thanks for the feedback, guys

evot23

iTrader: (17)

Thats what I suspected...I was doubting myself there for a second.

Thanks and good luck...let us know what they find.

KevinK2

tailhappy .. carefully fill system. purge all air out a few times, with short start-idle-stop-top_off itierations. Then drive a bit till fully warm, stop and park, eng off. After about 15 minutes, eng still warm, carefully remove fill-neck cap. IF pressure is relieved (no vac) and level is down there and at AST, then combustion gasses are being pumped in.

Another test is to run clear tubing from ast overflow to bottom of a jug of coolant set on IC duct. Start car and idle till fans cycle on/off. See if flow of bubbles from ast ... and no apparent end to them. If so, bad news.

evot23 ... if no ast, then a T2 filler neck top must be used (2 bolts to attach) with spring cap there. This T2 top has the zero pressure nipple that goes to the overflow tank.

evot23

iTrader: (17)

Kevin,

Thanks, I did the AST elimination about 6 months ago with no ill effects. Have the spring cap, was uncertain from some of the earlier posts if I could get away without one. I didn't think so and neither does anyone else.

Thanks again!

TailHappy

Thanks for the tips, Kevin. I probably haven't burped it right. I flushed the system, drove it about 10 minutes, let it cool completely down, checked level and it was fine. Then I've just been checking it every night/morning and adding as necessary. I was wondering if maybe I was getting heat sink since it's been 90-95 here the past couple of days. I had just gotten frustrated with trying to burp the system because it seemed like it just kept filling up my overflow more and more until it spills out on the side of my car.

And that's a TERRIFIC tip about running the clear line to a homemade overflow. I had read that you could see bubbles in the overflow, but then Mazda was nice enough to completely hide our tank so I figured I couldn't use that trick.

30 more minutes 'till I hear what the coolant pressure test revealed......

badass7

Been there done that. If you want to know the TRUTH about your engine do two things. Do a pressure test on your coolant system. If there are no apparent leaks from any of your coolant lines and a Drop in pressure....that means there is an internal leak !! Next thing is to do a Combustion gas test on the Coolant system. There's a kit that connects to the filler neck that contains a chemical. If that chemical changes colors (Bright yellow) from blue....then you are definitely getting combustion gas bypass through your coolant seals. Don't waste anymore of your time and stop playing mind games with yourself. It's torture. I know this first hand...because I just went through it myself !

badass7

BTW, NAPA auto parts carries the "Block Tester" and fluid. I believe it goes for around $50-$80. That is kind of high so I suggest you just find an auto shop that can perform this test. Nevertheless..if you do have a bad coolant seal....your car WILL last at least 6 months and maybe even longer. Just keep that radiator full and drive that baby to the ground. You may even want to try that block seal and run Evans Coolant from Pineapple racing. You can definitely postpone the rebuild. Last time this happened to me I drove the car for months until one day there was just too much coolant getting into the combustion chamber soaking my plugs. It never started after that. Rotor On Man !!

atihun

So what is the outcome?

Pumped

somthing is wrong with mine aswell, but my ast and filler is full, just my overflow tank overflows coolant to the ground( just a bit)

ruos

iTrader: (1)

I had water a leak last month the buzzer will go off once a week did the pressure test and it turnout the plastic end tanks of the radiator was bleeding water at high pressure. So thats when the fluidyne came in.

TailHappy

Well, nothing but inconclusive results so far. The pressure test fell through....the guy never could get to it and I had to have the car back. Then I went home and did the hose in a bottle test, but I'm not sure it was totally conclusive. I ended up having to add water right before I did it since I blew coolant everywhere when I opened the cap. (Question 1: how come when I pulled up the lever, it released some pressure, but when I opened the cap it still spewed everywhere???) I did the test and it bubbled a little, then quit for a while, and then started bubbling and blowing coolant about once every 10 seconds or so as the cap kept opening and closing from the pressure. Seems like that probably points toward the worst, but on the other hand it seems like if you boiled the coolant it would do the same thing, or the same if I had any air left in the system.

Which leads to another question. How does the system ever pull coolant back from the overflow??? It seems like the hole is on the other side of the springloaded cap, so the only time it is open is when there's excess pressure in the system, which would always push the coolant instead of pulling it! Probably too obvious for me to see it.

So I'm more or less back where I started. Good tips badass7. I'll try that next. And it is torture. I keep bouncing between it's blown, deal with it, and denial-maybe it could be something else. But I'm starting to see the bright side...if it's blown I'll have the thing built right next time and ultimately will end up with more HP. 274 wasn't enough anymore, anyway!

Just glad to hear that I have some time to start saving. I couldn't afford to take that hit right at the moment. And I really wanted to finish out the autocross season.

One more thing, once you knew it was blown, how did you go about filling it? Did you just wait for the coolant buzzer, or did you fill it every morning, or what? Seems like the buzzer likes to come on after I've been driving 3-4 minutes and everything's hot. So I'd just been doing it every morning which seems to be good for the day.

Also, I had a buddy in a second gen that had a good idea. When his seals went, he put a switch on his fuel pump so that he could turn it off and crank on the engine a few seconds to get the water out, and then would flip the switch to start the car. Whatever it takes!

Thanks again for the tips and moral support! I still luv my rx-7!

(but I still hope it's just a radiator!)

badass7

Well, read carefully. If your leak isn't that bad you should be able to drive around without having your buzzer go off after only a few minutes. In my case, I would check the filler neck when the car cooled down to see where the level was. I found that if I didn't fill it up all the way ie: keep it to where you can just see some coolant at the bottom of the filler neck (~3 inches from top). This allowed room for the extra pressure in the system to stay at a level where it wouldn't push any coolant into the overflow. However, if I ran it hard....of course too much pressure was built and it would push a bit of coolant out to the overflow. So, what you should do to determine how bad your leak is check the coolant and fill it like I said above and see how long it takes for that buzzer to go off. If it goes off after only 10 minutes or so after driving that's a major coolant seal leak. That means that a great amt. of coolant was pushed out through your overflow tank in a matter of minutes....not good at all. If that's the case it may not last very long at all.

TailHappy

Cool, I'll give that a try. For the record, I did all the flushing and refilling on Sunday, and then didn't touch it until Thursday morning when the coolant buzzer came on within 30 seconds of starting it. This morning I checked it before leaving and the AST was about half-way empty. I think these really hot days we've been having has aggrivated it somewhat.

Still curious how it normally pulls back from the overflow when the spring seems to seal that chamber off under normal conditions, if anyone knows....

KevinK2

Thee center of the ast relief cap has a small metal poppet valve on the bottom. vac will pull this open to allow flow reversal, pressure helps close it.

Tom93R1

iTrader: (2)

And that valve is why you need to make sure you have a non pressure relief type valve on the filler neck. If you have a pressure cap there that valve will open up under vaccuum and suck air in instead of coolant from the overflow.

user 84205

Hey bro, I currently have the same problem. As far as I have found out you can drive it till it breaks. Mine isnt as far along as yours is, Its not seals, its a defect that sometimes happens for some reason, the housing just develops a small pin hole crack. Mazda says some cars run like that for years, people just keep adding coolant. The only thing is the car gets to be a HOG, poor gas milage due to buring the coolant and fuel going into the water. Fouling the plug... IT SUCKS!!! Ganbatte= GOOD LUCK

badass7

Tailhappy, a few more important tips. When filling the coolant to where I told you to you MUST make sure that the AST is filled to the top. So, first thing every morn....check the AST...top it off.....then fill the filler neck up to where you can just see it at the bottom of the neck. Another thing you can do to see how far along your leak is.....drive you car fairly hard the night before and the next morning...pop your two bottom plugs. Stick your finger in the holes and at the same time crank over the engine by hand. This can be done by putting a socket over the main pulley and just turn it. you should be able to turn the pulley with your left hand while having your finger in one of the holes. While doing this check for coolant to leak out onto your finger. If there is no coolant your leak may not be that bad YET.