robind1

Hello...My '93 Mazda RX7 Coolant Alarm went off yesterday and my husband poured in some coolant and took it for a ride and it seemed to be happy. Today, he checked the coolant and it was empty again. FYI.... We replaced the engine @ 50k miles (following apex seal failure) and now the 2nd (remanufactured) engine only has 30k miles on it. I've been told that the Coolant Alarm/leaking is an indication that the engine's apex seals are about to blow (again). I've got the car for sale for $12,500 and have now been told to drop the price $2k to $4k, because the engine needs replacing.
Can anyone give me a definitive answer on this. How can I be sure that the engine is about to blow? Why isn't it possible that I drove it one day @ 30 degrees, and the next day I drove it it was 80 degrees, and the stress of the different temps could be a cause? How can I be sure? I'm just a girl with a beautiful RX7...changed the oil every 3k miles, and take care of it...It has no mods and All mazda recalls have been done. Turbos are real strong, since I drive it gently (which I've been told contributes to apex seal problems), so I kick-it past 5k on odo weekly in each gear to keep the carbons cleaned-out.
Please help!
Just a Girl!

Gen2n3

iTrader: (1)

Have you done anything to the coolant system - such as a coolant flush/refill? Make sure both radiator caps are on the appropriate ports. The spring loaded cap should be on the AST and the flat cap should be on the coolant fill port.

Does your coolant dump into the overflow tank? Do you blow any white smoke out the exhaust? Are there any other oddities that make you say, "Hmmm?"

Mahjik

iTrader: (1)

Just FYI,

Coolant buzzer doesn't mean your apex seals are going to blow. The analogy with the coolant buzzer is the "coolant o-rings". However, it can amount to the same thing, a new engine if the o-rings have failed.

The first thing to do is to have the coolant system pressure tested. Just about any auto shop can do that. That will let you know if there is a problem with the cooling system.

Good luck.

Eggie

And ask them to check the line to the overflow tank.

RotorMotor

iTrader: (5)

there could be a few potential problems that could be causing this and you need to figure out which one it is. if youre pouring coolant in and its disappearing a day later its obviously going somewhere... so lets figure it out. there are a few possibilities

1: the coolant is "boiling over." Coolant expands as it gets hot, and the extra expands from your radiator through a tube to your overflow tank... and if that fills up it will spill out of that tank (looking in the engine bay its a plastic cap on the left front side where you can put coolant into). If this is happening your car is OVERHEATING, and the coolant is exiting from that clear plastic tank after it fills up, and you will notice coolant leaking out from under that tank after you add coolant and stop after a bit of driving.

There are a few causes for overheating:
-Not enough coolant in the system, or air-bubbles inside the coolant system.
-broken thermostat
-broken fans (or relay to the fans) which cool the radiator
-missing underbelly cover on the bottom of the car
-broken waterpump (although they rarely fail)... or a slipping belt that SPINS the waterpump (definately a possibility).

Just a quick side note to make sure your husband KNOWS WHAT HES DOING when he says hes "filling up the car with coolant" . There are 3 caps for coolant on the rx7. The black plastic one on the clear tank (the one we just talked about at the left front of the engine bay). this is NOT-pressurized... its ok to open it with the the engine hot. fill it up to the full mark with 50/50 water and antifreeze (i use distilled water personally for all my cars to avoid mineral deposits).
next cap is in the middle of the engine on top of the water-pump housing. this cap should be yellow and read "do not open". it is under pressure so dont open it while its hot. this cap is just a basic seal cap... but make sure its not leaking when on. you can add coolant here as well when the engine is cool... and its through this cap that you want to add coolant when removing the air bubbles from the coolant lines. there is a procedure for removing the air that i can list later... but this needs to be done to make sure that air in the coolant system is not causing an overheating condition. (by the way, the sensor thats causing the low-coolant beeping is in the housing that this cap covers.... if you add coolant here the beeping will stop when it sees the right amount of coolant. but if you are LOOSING coolant we need to figure out WHERE. fill this up with 50/50 coolant and follow the procedure for removing air from the rest of the system. this is also the cap you will look into for bubbles when we talk about loosing coolant through the motor later.
the last cap is on a black (or metal if its upgraded) cylinder or container called the AST. the AST is supposed to help eliminate air bubbles from the coolant system but it doesn't work if theres a ton of air in the system. the cap covering this has a spring inside the cap. when the pressure of the fluid gets too strong this spring is forced open and coolant is allowed to exit through a hole near the top of the AST which is connected to a small hose that you will see at the top of the AST. this hose goes over to the clear tank ... thats how the extra fluid gets into that clear tank when the coolant expands too much. as the coolant COOLS it will be SUCKED back through that tube... so if everything is working right and your not overheating you should not loose coolant as it gets pushed out when hot but sucked back in when cold.

now you hopefully have a begining understanding of how the components connect to each other (if not please feel free to ask). there are a few other parts i should mention that make everyhting work together. the thermostat (a potential cause for overheating) is a valve somewhere under the middle yellow cap that allows coolant to go from the motor to the radiator when the temperature gets too hot. this may be broken or not working properly. this (for example) could cause the coolant to not be cooled by the radiator and get to hot, which would cause the pressure to rise, which would in turn open the spring on the black AST cap which would cause coolant to go into your clear plastic overflow tank with the
black cap. the coolant could then spill over out of the car. when everything cools back down you will now have less coolant and your buzzer will ring. this is just one example of the chain of events which could cause the buzzer to go off. But dont worry we will help you get to the bottom of it.



2. If you eliminate the other possibilities and are not overheating and "boiling over" the next problem could be a LEAK! There are alot of hoses and tubes that make up the rx7's cooling system. any of these could have been installed incorrectly, too tight, too loose, have a small hole etc etc.
If someone wants to list a picture of the different hoses to examine that would be great. there are a few main ones (the big ones that go to your radiator), the one from the AST, a few in BACK of the motor, some on top of the turbo. being an rx7 they are all nearly impossible to see as they are all under other parts. the best way to check (i would think) if you dont have the patience to look for every one is to fill up your car and see if anything is dripping underneith. if an area of the engine bay (front, back, left right) is dripping coolant we can help point you in the direction of the suspect hose. could just be a simple hose. who knows.

3. the very last thing that could cause you to loose coolant (not dripping out of a leaky hose or boiling over) is for the coolant to be SUCKED into the engine and blown out of the exhaust. this could be because of a faulty coolant seal (separates the coolant from the combustion chamber). if this seal fails you will notice a few tell-tale signs.
-remove the yellow middle coolant cap (when cold) and fill up with coolant. leave the cap off and put it somewhere safe. now start your motor. do you see a bunch of bubbles coming to the surface?? do you see oil floating in the water? its normal for the coolant to rise as the motor warms up and for TINY bubbles to come up, but nothing big. if you see large bubbles you may have a bad coolant seal which will require your motor to be rebuilt. remember to put your cap back on after checking!
-look at the tail pipe. do you see lots of water or WHITE smoke coming out CONSISTENTLY? not a bit... a PLUME of white smoke that doesn't stop. if there is a bad coolant seal you may see white smoke... which is actually steam from your coolant... it will have a somewhat sweet smell. this is another tell-tale sign.


one of the previous conditions WILL be your problem... we just have to narrow down which it is. please ask any questions that you have regarding procedures or clarifying what things are. the rx7 is somewhat complicated... but once you understand how it operates the causes and symptoms will make more sense.

-heath

evo2fd baby

^^nice

Mazda99Nikon

Good job Heath. Learned a little something here, myself.

Rx-7Addict

iTrader: (2)

If your coolant seals are blown (time for a rebuild) you most certainly would have described a huge cloud of smoke from burning so much. My guess is you have a coolant line off or a leak somewhere ... see RotorMotor's post for more detail.

Eggie

Good reference info found here.

Gen2n3

iTrader: (1)

Damn, RotorMotor that is a sweet write-up!

robind1

Hello Folks...Thanks for all of your input! ...Below are responses:

Some white smoke on startup

Coolant was low the next day after filling from the “do not remove cap”

No coolant on the garage floor that would be from a leak

Some liquid coming from the exhaust pipes. Not a sweet smell from the exhaust. More of a strong exhaust smell. Burns your eyes.

Our plan is: We will fill it when we get home and do ecommended tests. Looking for burping bubbles.

THANKS MUCHLY...Will let you guys know the results!
Just a Girl w/ a Sweet RX7!

gracer7-rx7

iTrader: (16)

Can someone recommend a rotary/ RX7 specialist near them in Severna Park, MD? It sounds like they are going to need one....

robind1

Here is my status as of today:
We have a little smoke at start up and after about 10 seconds, no smoke. On Sunday, the coolant buzzer went off for the first time. We put about 8ozs. In it to fill it to the top. We rode it some, about 10 miles, came back and let it semi cool down. After about an hour to an hour and a half, We looked at the fluid level. It was down but we could see it. We did not use it until yesterday. Here is what we did yesterday:

We filled the radiator up. This required 2 ozs. Of fluid. We ran the car with the cap off. There were no big bubbles coming from the cap. As it ran, we noticed brown floating to the top. Not much, but some. I don't know if this is oil or rust from the radiator line. When Mazda did major work back in January (front cover seal, front main seal, oil pan gasket seal), they said the radiator system was very rusty. We checked the oil level and it was full. We can't determine the smell (sweet or not)from the exhaust. There are no fluid leaks under the car.

I would hate to take a bigger lose on the car if this is possible a minor problem. Is there anything else We can do to determine if oil is in the coolant? Some kind of test? I checked the fluid this morning and it was not to the top but I could see it. I will continue to monitor the coolant level. We don't see any leaks under the car but maybe one of the hoses has a small hole leaking the fluid which is evaporating on the hot engine. Could this also be possible? Maybe have the collant system pressure tested to determine if a hose is leaking.

Thanks for your knowledge and any help.

Mahjik

iTrader: (1)

A pressure test does more than just tell if a hose is leaking, it also verifies that your internal coolant o-rings are holding. It checks to see if the 'entire' cooling system can hold pressure.

Montego

iTrader: (1)

I hate that test... Is not definitive at all. Rust in the system can cause bubbles and create a champagne foam.


oil in the coolant and vice versa is easy to check... As oil and water don't mix so it creates this weird cream in your oil pan. Check the dipstick. creamy= problems.


By your symptoms it does not sound like you a have blown coolant seal. A coolant seal failure typically collects coolant in the combustion chamber and upon start up the car shakes extremely at idle while blowing tons of white smoke. After a couple of minutes the shaking stops and so does the smoke. After that the car is as if nothing has happened other that you have to keep refilling your coolant and possible overheating.

I bet you have a leak in your system. After driving your car for about 20 minutes and shutting down do see coolant on the floor near the passenger's front tire?

robind1

I had the car in the garage and there was no liquid on the floor. I got a recommendation for a rotary shop, Kearney Automotive in Capital Heights MD. After talking to them, I'm thinking that it could be a small leak in one of the hoses that is evaporating from the heat of the engine. They said I could bring it end at the end of next week. I will continue to drive it and make sure the coolant level is ok. They tend to agree that it probably is not the coolant seal with the problem.

TpCpLaYa

iTrader: (10)

if thats the case, a very easy fix would be to warm the car up to full operating temperature, pop the hood and peak around. A leak that evaporates instead of drip to the ground will easily be noticed with the presence of steam. The end tanks on the stock radiator are plastic and prone to leaks...even if its a small one likeit may be in your case. Try getting under the car to get a look up into the radiator and engine. At least its worth a try and might save you some money instead of paying the shop.

robind1

There is no leak on the ground. I'm thinking it may be evaporating on the hot engine or hot turbos. I'm having the system pressure tested on monday. Hopefully that will determine the best outcome.

RotorMotor

iTrader: (5)

i still think you are overheating, and maybe the coolant is leaving while your out driving. or there is a leak and youre not seeing it for some reason... but id think if something was leaking to the point that it would activate your low coolant sensor you would see it. i still think there are bubbles in your coolant system which need to be removed.

scotty305

iTrader: (2)

I'd start by double-checking simple maintenance items first. It shouldn't cost more than $50-75 if you do the work yourself:


1.) New pressure caps. Replace the one on the Air Separation Tank and the one on the filler neck. I use a 16psi cap for the AST and the OEM Mazda cap for the filler neck.

2.) New thermostat. I personally recommend drilling a couple of small (less than 1/8" diameter) holes in the outer ring of the thermostat, but not everyone agrees with this.

3.) Coolant flush. Do this while you're replacing the thermostat, as you'll be losing some fluid anyway.

4.) Don't forget to properly burp the system after refilling the coolant! A good coolant funnel is one of my favorite RX-7 tools aside from my Mechanix gloves. See the Big Fat FD3S Cooling Thread ( https://www.rx7club.com/showthread.php?t=571088 ) for a link, the one I have is manufactured by Lisle.

5.) Be sure that the hose between the AST and the overflow tank is sealing properly. You might want to add a hose clamp to seal where it connects to the AST. For a little more info, see the last paragraph of the Maintenance section of the Big Fat FD3S Cooling Thread.




If there is a leak, you'll find it by doing a cooling system pressure test. Install the tester, and start the engine and let it warm up for 10-20 minutes. It's possible to have a leak that only happens when the system is warm. After you shut the car off, leave the pressure tester on there for at least 30 minutes. Some people like to pump the pressure up and leave the tester overnight, to check for very slow leaks.


-s-

rotormart

i had the same problem i thought i needed a rebuild but instead i bought a new coolant system new rad,thermostate,hoses,water pump and caps,fans and i have not had a problem since.

SLOASFK

iTrader: (5)

JPR in Marlton, NJ. KDR in Bethlehem, PA. I only know of one shop in MD and they specialize in FCs...

And of course, there's always Rich and Ihor's shop in Clifton, NJ...but they are overwhelmed trying to fix my car right now