The Ace

OK, I've been having all sorts of little teeny weeny problems with my TII lately, although I try to keep it 100% healthy....anyway, I think you all know about my coolant problem that I've been having lately. Car does not burn coolant, but somehow if I turn it on and off a few times, coolant goes over to the overflow and stays there, at least until it cools down completely (like, the next day ).

Anyway, after changing (again) rad cap and some of the little hoses, problem seems to be -somewhat- fixed. So I say to my g/f "ok, lets go to my summer house for the weekend". On Monday morning (public holiday in Greece) I drive her up to the mountains to show her the view (nothing naughty, just the view ). Although I drove very slowly (in order for her to see the surroundings), and I didnt boost much, the outside temps were VERY high, and it was 12 high noon. I think I did a mistake and didnt leave the car to cool down much (just 30 secs or something), and I turn it off.

Well what do you know, when I try to start the car 20 minutes later, no go !! The plugs wouldnt fire (thats the way it sounded). I pop the hood, and the overflow was FULL Not only that, but as the car cooled down, more coolant was going to the overflow (the overflow tank was getting more coolant by the second) Whats more, when turning the key to the "ON", the boost gauge wouldnt go as high as "0", it would just stay halfway between bottom and "0".

Anyway, I tell my g/f to relax, as this would take a while I start doing all the usual stuff. Reset ECU, check fuses, check hoses all around, check AFM, slowly release pressure in radiator and put the coolant back, disable alarm (dont know why, just a thought), try again, nothing. Well, after 5 or 10 minutes, after letting car cool down some more, I give it a try again, and after 10 or seconds of spinning the plugs finaly fired, and the engine started up. Idled just fine, and drove the car for more than 45 minutes after that with no problem at all.

When I returned to my house, turned off car, checked overflow, fine. Tried to start the car, started right up first turn of the starter.... Could it have been just the heat ? No buzzer, no overheating although almost all the coolant was in the overflow....

Any ideas anyone ?

SonicRaT

iTrader: (6)

Are you boiling your coolant? Does it sound like popcorn popping after you turn it off? I think either you have bad seals (pushing air into your coolant thus pushing it back up into the overflow), or your boiling your coolant it's going into the overflow container, those are the only idea's I have.

The Ace

Well, when the car was cooling down (turned off), there was just this gurgling sound from somewhere in the upper radiator hose area (either from the hose or the radiator).

What I dont get is that this is not constant behaviour. I mean I drive the car for 40 minutes to go up the mountain, and all the coolant was in the overflow. I return the coolant to the overflow, i drive the car for another 40 minutes with the exact outside temps and in the exact same manner, and the coolant stays in the radiator

I guess its one of those "magic" things that the Rexes do... I swear, all of my previous cars combined had less than half the problems of the Rex.... Still love it though

EDIT: but what about the "no-start" issue ? Didnt know that not enough coolant in the radiator prevented the car from starting....

SonicRaT

iTrader: (6)

That gurgling you are hearing is boiling, extremely bad! This either means you are letting air into your system from somewhere, or your car is overheating, what does your gauge read? Do you have an aftermarket? Can you get an aftermarket? I'm not sure, but that's exactly what my did, just spewed it out, and then after that, I filled it back up and started it up, and it was fine, hasn't filled the overflow again at all. Have you had your system pressure tested? Have you checked the thermostat (probably) How about the water pump?

The Ace

Buzzer didnt come on, temperature was normal, stock gauge was moving slightly up and down around halfway where it is supposed to be (obviously following the open/close cycle of the thermostat), thermostat is brand new, system pressure-checked just fine, dont know about the pump though (cannt test it myself, and the mechanic at the Mazda shop says "no reason to check, its working just fine"

But why is this happening on and off ? One minute it'll happen, the next it wont....Obviously it needs to reach a certain temperature, but even if it does (like yesterday), it wont do this consistently

I know it MUST be a tiny hole in the seals somewhere (mechanic tested it and said that he did see a veeerrryyyyy slow flow of tiny bubbles, like one every 10 minutes ), but still why is this not consistent ?
Man this is weird....

SonicRaT

iTrader: (6)

I'm not sure as to why it's not very consistent, but that gurgling sound can be only one thing, boiling, or a MASSLOAD of air being dumped into the radiator, but if the cars off, that doesn't seem possible. Have you flushed/changed your fluids at all lately? I don't know how it could boil being only halfway, that sounds a tad strange. Good luck, I am out of ideas!

The Ace

Yeah, thats about the same situation as I am in... and this is my car

Thing is that when the car is on, nothing serious happens, everything's fine. When I turned the car off, then I noticed that the overflow was full, the gurgling sound, and that the coolant was moving TO the overflow and not FROM the overflow back to the radiator... How is that possible ? If it was exhaust gases, wouldnt that mean that the engine would HAVE to be running in order for this to happen ?

It could also be some tiny hole somewhere in the coolant lines, sucking in air during the cooling down process (but not letting coolant out). Back to the shop it is, I guess....

Hot_Dog

Hey Ace,

A couple years ago, I noticed that during the summer months the temperature gauge on my '90 RX7 GXL would start to approach the hot region when I ran my AC. After going through lengthy troubleshooting procedure, which included changing the coolant, radiator cap and thermostat, I decided that I would replace the fan clutch since everything else had been replaced already. BTW, the old fan clutch, which was the original with with about 170K miles, offered some resistance to rotation when hot while doing the manual spin test. Therefore, I didn't think that the clutch was the problem, but I was running out of possible causes. So, I replaced the fan clutch and surprisingly that solved my problem. If you haven't checked out your fan clutch yet, than I'd suggest adding that item to you troubleshooting check list. Just my 2 drachma.

LJM

Cheers!

maybe the temperature gauge and sensor stuff is no longer working properly, therefore the buzzer isn't going off.

The Ace

But you see, I dont get any overheating, and although my fan clutch does seem to be somewhat slippery, it can maintain its proper rpms no problem...

Marco

As you know I have a simular problem with my car and I noticed this behaviour also a few times, mostly when it was hot or when I drove the car hard. I thought a lot about it and came up with the following explanation:

When you turn of the engine the temperature of the coolant allways rises, because the engine is still hot but there is no flow of coolant through the radiator anymore and no fan blowing etc. (this is one of the reasons why you should keep it idling for some time before shutting it off, the other reason is the turbo). Higher temperature means more pressure in the coolant system (because the volume stays the same). Because the pressure was allready high because of the exhaust gasses leaking in the coolingsystem, the radiatorcap opens to get the pressure down. This radiatorcap opens when the pressure gets to high to let out some coolant in the tank. So when it opens the coolant gets out and the pressure drops so the cap closes again, the pressure rises again until the caps opens agian etc. This is why the coolant flows in pulses to the overflow tank (as it did in my car). This will stop when the temperature stops rising and the pressure starts to drop.

This symptoms all could get even worse when the coolant starts to boil after shutting the engine off. I can imagine that in that case the pressure rises so fast that the radiatorcap doesn't close anymore and you get a constant stream of coolant in the overflow tank. Do you see steam or exhaust gasses coming from the overflowtank? ( I did, even when the engine was off!)


I think that the coolant wouldn't boil when the problem is high pressure because of the exhaust gasses. The pressure is simply to high for the coolant to boil. But when you have a pinhole airleak or something like that the pressure would drop rapidly when you shut of the engine and in that case boiling coolant gets very likely.


Marco.

The Ace

Hmmmm, a somewhat accurate description of my own problem...hey Marco, I see we are in the same boat I knew that when you replied to my last thread, but your post now only makes it final: we must have the exact same problem...

Anyway, I'm asking this in another thread, about why the stock e-fan does not come on at all, in order to cool down the engine a bit...if this is normal, then RX7 should be left to idle for A LOT LONGER than any other car, even when you have not pushed the car to high boost levels (i.e "racing")

Thing is I never see any exhaust gases in the coolant or in the overflow (and I have looked, believe me ) I can only see this behaviour at certain occasions (must be when its really hot outside, or when I have turned car on and off a few times within the day). Does this mean that I am doomed ? Naw, I know its just that I have to look out for my coolant levels every two days or so, but still....


Hey Marco, what is up with your attempt to fix this ? Any news ? Have you tried anything yet ?