Stevey629

I know this has probably been posted before, but I couldn't find anything that matched this description exactly. But I felt like being detailed, so here it goes.
Ok, we all know the stock temp gauge is worthless, but the car is stock, so thats all I had, but it was enough to tell me that if that needle ever got above the middle line.... stop, drop and roll. Basically, after a normal drive, good hour or so, everything seemed to be going fine, when I hit traffic. Came to a stop, and was cruising along at speeds that this car does not like to be driven at... i.e. stop and go. So I decide to pull out of traffic and get into a slightly faster lane, get on it a bit, and wham. The temp needle starts headin for the sky, and the buzz sound for the add coolant light starts up. So I immediately pull over, and once I come to a stop, the buzz stops, warning light shuts off, and the gauge goes back to normal...everything seems fine. I continued to my destination and shut the car off. I noticed a black cigarette ash-like sludge/film on the dipstick for the coolant after inspecting the level. But after starting back up, No lumpy idle no apparent problems, neither any apparent loss of coolant. So I head back home (approx 30 mins away), and the warning light and buzzer came back. This time, I pulled into a nearby parking spot and tried to do the same thing that I did before, but this time, the needle kept climbing, and I shut it off. I popped the hood, let it chill out, even though the motor didnt seem to be hot. I tried just clicking the ignition to ACC without starting the car back up and the needle shows the temp was still high (high meaning above the middle) and the buzzer came on after the standard beep noises from the double key click were through...So I took it to a gas station, luckily really close by, came to a stop near the air/water station, and noticed a puddle of coolant/water under the car, about the size of a decent sized breakfast pancake. I doused the radiator in water, and sprayed air on the radiator, in hopes of cooling it off enough to just get me home, even though it didnt seem hot, wasnt smoking or steaming, or anything. So I head home, and it happens one more time, this time it was like the first; I just pull over and the buzzer shut off. From this point, I dont know what to think. Im assuming I am due for a coolant flush, as I am worried about all that mess in the coolant, but I am also worried about that leak. Are there any common problem areas that I should look for as far as the leak goes? The puddle of coolant was closer to the passenger side just in case this may help in diagnosing the problem... This situation basically left me very confused and more importantly very worried. Any help with this would be greatly appreciated.

artguy

the number one common problem is that you should not have been driving the car at all like that. period.

you may have turned a coolant flush problem into a complete o ring failure.

NEVER DRIVE THE CAR UNDER ANY CIRCUMSTANCE if it is overheating.

at this point you can flush the system...and pray. be sure to burp it...get all the air out....all of it.

I wish you luck...repeated overheating damages the side seals and the o rings. both of which require rebuilding the motor.

if that ever happens again...pull over and call your friend..call a tow truck...get a friend or family member to help you tow it if you have to...DO NOT drive it. got me?

a tow truck is 50 bucks or so....a motor is 2500 plus labor and most likely will be more...new housings if you warp them etc...

you may have just boiled your coolant over which would explain the leak...you probably have air in the system which will do it every time...did you hear any gurgling?

but you might also have broken a seal..worst case scenerio...

j

Nathan Kwok

It sounds like you have a stuck thermostat. When that happens coolant can't get through to the radiator and the car overheats. This causes the coolant to boil and overflow into the overflow bottle. Then when the overflow gets high enough, it uh, overflows, hence the puddle near the passenger side. There is a small hole in the filler neck of the overflow bottle so you won't actually see it coming out. Don't worry about the black sludge for now, but what I would do is get it towed to the nearest rotary mechanic (or if you can't do that, nearest trustworthy mechanic) and have the thermostat checked and replaced, then have the entire system flushed with water, all hoses inspected and replaced if necessary, and then fill it back up. This will probably cost about $100 or so. Also make sure your fans are coming on properly and that the radiator isn't clogged. Run 50/50 (cheapie green coolant only) and no water wetter. You shouldn't need to run water wetter or a high water/coolant ratio to maintain reasonable temps during normal driving. As for the black sludge, this is very common, and once you clean off the dipstick and flush out the system it shouldn't come back. I often have a little black bit clinging to the dipstick and I just flick it off, I think it comes from the hoses slowly disintegrating. As long as the coolant in the AST looks clean and doesn't have oily residue or other stuff in it you are fine.

artguy

sorry for the "what not to do" post...but every time i see someone on here doing that..it freaks me out.

j

Stevey629

ok, thx for the help guys. And artguy, ur absolutely right and I agree, Ive heard horror stories about overheat probs, and when that light turned on, I pulled it over as fast as I possibly could with traffic, then like I was saying, drove it home. I was saying the same thing to myself, "dont drive it moron". Stupid to do, yes, but I was down the hill from my house, and the car seemed to be running fine, with no signs of serious heat anywhere. Better safe than sorry, but the situation that I was in didnt exactly give me a whole lot of time to call a tow truck and have it towed up the street. Then again, I dont have that much money for a rebuild at this point either...double edged sword if u know what I mean. I have yet a lot to learn about the cooling system. Slap me if I ask this, but where is the overflow tank and ast tank, and what a good one is supposed to look like. Is the AST tank right next to the intercooler? Anyhow, there is no way for me to really learn unless I break something first, if I havent already...so if u could teach me or send me some kind of link that has a breakdown and pics of what every part of the cooling system does and where its weak, maybe I can keep this from happening, or if it happens, I will know what to look at and look for. And if I caught the prob early enough, I can avoid problems in the future. Thx for being supportive, and courteous. I appreciate it.

Stevey629

oh another thing. my friend and I were planning on doing the coolant flush this weekend after thxgiving, and is there any way to check the thermostat on my own? If not, then I'll try to get it towed to a shop and have them do the whole deal, flush, hose check, etc. And why not use watter wetter? If it can lower the temps, how could it hurt? What ratios of water to coolant are best for reliability, because at this point, thats what I really want. I just want the temps down, with out stuff cloggin up. Again, laugh at my stupidity with this, but I need to learn this sometime, and again I really appreciate the help.

crazysuprakid

If the car overheats is the best thing to do pull over immediatly and turn it off or should u let it idle or what?

Street King

AST is going to look greenish with a metal cap by your IC on the driver side. Radiator is by your altenator and over flow on passanger side I believe. The overflow will look like a big ole' plastic thing, lol! Make sure you don't have any leaks and squeeze tests all the hoses to make sure they are still flexible. Since you are in San Diego you can go ahead and use 65/35 water/coolant. I use that plus I added water wetter even though it goes against some people's choices, find an answer for your self. It's important that the system is completly "burped" after you flush it. Fill the radiator up, then top off the ASTT, then make sure the overflow tank is at the level it should be. Start the car let it idle for a while might even wanna take it for a quick spin(1 min or less). Go back and check all 3(after it cools a little down) and fill them up. You won't get all the air out in 1 day so carry some water/coolant mixture in your trunk and every day go out to your car to keep filling it up. Should take a week depening on how often you drive. Good luck and I hope you didn't do any damage which looks like you didn't.

pomanferrari

iTrader: (1)

You have the dreaded "blown o-ring seals" syndrome.

If the symptoms will not go away, don't worry, get 3 bottles of CRC copper block weld, do a search on this forum, follow directions and you should be OK. Disclaimer, make sure that your seals are really gone before you do this ghetto fix though like pressure test system, replace hoses, thermostat etc b/c these things can be reused if you really need a new motor.

pomanferrari

iTrader: (1)

BTW, my car has been running fine on this ghetto fix for the last 6 months, boosting 13.5-14.o psi with M2 IC, PFC, PFS CAT BACK/DP ETC..

spurvo

I'll throw in here (for no other reason than I'm a post *****!!) that the thermostat really isn't that hard to do your self, especially if you are already in the middle of the flush job. GO TO MAZDA for the thermostat, this is one part that really needs to be OEM (tighter temp control, opens when it's supposed to, and has the pressure relief hole to aid in filling). I'd replace the thermostat, THEN see if the engine is still spitting up coolant on driving. If it is, THEN think about o-ring failure. With the cooling system, go for the cheap fixes first.

Black stuff on dipstick is: 1) if you JUST replaced all the hoses, this is the rubber coating on the inside of the hoses coming off and collecting in the overflow tank; 2) if the hoses are more than 1000 miles old, you are seeing the result of cooked coolant from the turbo coolant circuit. This is normal, but does show why you need to cool the turbos off before shutting off the car so you don't cook the coolant at 450C!!

here is a cooling system diagram:

http://www.autosportracetech.com/RX-7/coolingsystem.htm

check out the rest of that site for REALLY useful information. Note also that if you run with your lights on, your fans should kick on BEFORE the temp gauge moves (stock set up, linearize that sucker ASAP, or get a real gauge!). The super fast rise you saw was very most likely a thermostat failure, followed by boil over, as has been discussed. You miiiight have caught it in time, but you will want to look for snowy white sweet smelling smoke pouring from the exhaust right on startup for the next few weeks. THIS IS NOT to be confused with the steam-like stuff that comes out about a minute after startup that smell like unburned fuel. THAT smoke is normal condensation boiling off the cats.

Look at the manual for T-stat swap, but in a nutshell, you pull the airbox and attendant hoses, the upper radiator hose, and the AST return hose (the upper one going to the aluminum housing on the front of the engine. Remove the three 10 mm bolts holding the T-stat housing on the engine, and pull the T-stat out. Replace with the new T-stat, remembering to put the T-stat into it's gasket (MAKE SURE YOU HAVE THE GASKET when you get it from Mazda. It SHOULD, but you want to be sure. DO NOT re-use the gasket!), and placing the T-stat back into the block the way it came out, with the little pressure relief hole sitting at the top of the t-stat. Put the T-stat housing back on, tightening the bolts to proper torque (or just tighten them hard, but not Godzilla as this is aluminum you are bolting into), and reassemble.

Fill with coolant as was mentioned. I found that pulling the throttle body hose allowed me to fill the coolant with the AST cap off, filling through the housing neck you just fiddled with. The coolant level will reach the top of the AST first, so cap it when it does so. Next, you will hear gurling in the TB hose. Watch that hose connection, and when you see a little coolant dribble, re-connect the hose. Top off the filler neck, close it up, and run through a heat cycle, WATCHING that temp gauge, WITH THE LIGHTS ON! The fans should come on well before the temp gauge moves past it's typical stuck in the middle position. Shut the car off AFTER the fans go off (this is so the engine doesn't get shut off at 210 F and heat soak. The fan shutoff should be 195F), or of course if the temp gauge goes past the middle position AT ALL! Let the engine cool COMPLETELY, and re-fill the AST and then filler neck. Carry the coolant with you to top off whenever you stop long enough for thr engine to cool off. This should get the air out.

Hopefully, your engine is fine. I just wrote a damn book!! sorry...

Street King

You should get a miata thermostat because it will open sooner than the rx7 one. Same fit and all. I believe the rx7 therm. opens at 180 deg. and the miata at 160 deg.

r0gu3

Fan switch mod and run the fans on medium all the time. Works wonders.

Stevey629

thx for the help fellas, U have inspired confidence. And spurvo, thx for the detail! I appreciate it. I am just praying that it isnt o ring faillure, but there are ghetto fixes from what it seems. I just hope I dont have to resort to that. Anyhow, the temp gauge mod and fan mod sound like a good idea. I dont wanna ask how u guys did that, I guess I'll search and see what I get. but if u wanna post, cool by me cuz I could use the extra help. THX once again.

spurvo

Please note: Many of the emission controlled functions on the engine are keyed in to switch on or off at 177F, so a 160F t-stat will cause you to run in cold mode. I don't have the manual handy to tell you all of them, but it is a pretty extensive list. Lowering temp through t-stat really doesn't address the issue, as this won't cause the engine to run any cooler once the t-stat is open. the importent things are cooling capacity (radiator, water to coolant ratio, heat transfer additives), system inegrity (hoses fresh, t-stat opening properly, AST replaced, radiator replaced), and the switch points for cooling assist, whether done through ECU (210F with an electrical load, 224F with no load, 228F to bring on med fan speed, low and med speed bumped one level when AC is on) or manually through fan mods. Note that peak hp in this engine is at 195F or so. On the freeway with the Miata t-stat, you are well below peak hp temp. Miata thermo switch switches at lower temp, though, so this does make sense if you wish passive fan control.

ZeroBanger

in MOST cases you are right, however Before I got my overheating problem fixed ....during a 105 degree day last summer I was at the track (didn't realize I had that much of a problem then) when I went to leave it was about 60 degrees at night, very cool and my water temps were 114. The needle was NOT in the red, but I am a few degrees away from a new engine. At this point I had to make a decision. Choice 1 was to stop the car let it cool down. Choice 2 is to pop the hood and drive the car. I chose choice 2 and it was the right decision. Had I stopped the car, the heatsoak would have been 130C+, maybe even 135C. That has to be as bad or worse on the car than when its running and at 130C.

I drove the car with the hood popped and it never went above the 114 that it was at, within a few mintues it went to 100, then 95, and eventually it hit 85C. The ONLY reason I did this is because there was NO traffic and it was very cool at night. Had there been traffic I'd have a new engine today (with a street port, lol).

You must realize the validity of my point.