loosing coolant! Please help!

[Lum]

My car has started loosing coolant from somewhere over the last 2 weeks. I\'ve no idea where from though! it\'s a 94 FD and i\'ts havin no problems starting and it\'s making good power so i\'m hoping it\'s not a water seal.
Hears whats happened so far. The car runs fine and doesn\'t seem to loose any coolant when i\'m driving, even on long trips. However when i leave it over night and start it the next morning the add coolant buzzer comes on within a minute:2eek
last night when i stopped after a ten minute drive i could see some water on the floor for the first time but couldn\'t tell where it was comin from. i couldn\'t open the filler cos the engine was hot so i tried topping it up via the expansion/overflow bottle by the headlight but this was at the correct level already.:xconfused
So it seems to be returning water to this bottle but not drawing it back out?
Any ideas?
Could this be a faulty AST cap?

[MillSpeed]

Bingo! First things first, inspect the AST cap and make sure the return valve is opening freely. In fact, just grab a new cap first as last...they\'re only about a fiver from any good motor factors.

[Lum]

ok i\'ll try that! can i just get any cap to go on there? as long as it\'s the right pressure obviously!

[MillSpeed]

As long as they\'re the same size. If you go in and ask for an RX7 one you might get a blank stare or spend half an hour while the bloke flicks through his big catalogue, but the one off the 1.8 Mazda 626 fits, that\'s what I\'m using at the mo. It\'s a 1.1 bar cap but I\'m sure the 2 litre model had the 0.9bar cap like on the FD.

[Lum]

Replaced the ast cap on sat new one was only £7! so far so good no coolant light all weekend!
Can\'t believe i managed to fix a problem with my FD for less than £10! Happy Days:rollin
Thanks millspeed!:cheers

[MillSpeed]

No problems fella! Glad it was a simple fix. Would be worth keeping an eye on things tho just to make sure all\'s well.

[Lum]

Rite seems maybe i jumped the gun getting all excited with my £6 fix!
The water level seems to be ok now and i don\'t think i\'m loosing any coolant however the add coolant buzzer is still coming on?
It\'s kinda random too, although seems to happen more when i\'m stopped in traffic!
i\'ve kept a close eye on the water temps via my power FC and it\'s never gone above 90!
Any ideas? (please don\'t say coolant seals)

[MillSpeed]

If the level\'s not dropping in the filler neck by the alternator (which would set off the low coolant buzzer) then there\'s a chance it could be a problem with the sensor or its wiring. If memory serves, if you earth the wire that\'s going to the level sensor the buzzer will sound, so it could be that the wire is earthing somewhere. Either that or the buzzer sounds when you disconnect the wire from the sensor (I can\'t remember off the top of my head). Either way, inspect the condition of the wire coming from the sensor. There\'s a second connector somewhere along its length which has been known to cause problems also.

[Grizzly]

Do you have an Aftermarket AST tank? if this is Placed low then you get an air bubble in the Engine filler, it should be the same level or higher.

Also check the Pipe that runs from the AST to the Filler bottle (drivers inner wing) mine had a Join in the center that was leaking and causing it to draw air in.

When the Buzzer goes off is it on and off quite quick bursts or just on

You can tell quite easy if your Coolant seals are going/Gone when you start it from cold sqeeze the top rad hose, if it goes hard withing seconds of starting and you can still hold it without being too hot you may have a problem. Also does it sound like the water in the engines Boiling when you run it up to temp and turn off? this is a sign there is a leak as water boils at a higher temp when presurized.  I would say do the Bubble test but i\'ve recently seen a few cars that it\'s not worked on.

[Lum]

rite i\'ll check both these things tonite! i have a standard ast so don\'t think it\' s that. The buzzer usually comes on for about a minute then goes away! It does seem like maybe an air bubble or something like that!
I havn\'t done many miles since replacing the faulty AST cap. Could that have led to air being drawn into the system?

[LRP]

rite i\'ll check both these things tonite! i have a standard ast so don\'t think it\' s that. The buzzer usually comes on for about a minute then goes away! It does seem like maybe an air bubble or something like that!
I havn\'t done many miles since replacing the faulty AST cap. Could that have led to air being drawn into the system?

?? come on round will hav a look bring a torch as mines

[Grizzly]

rite i\'ll check both these things tonite! i have a standard ast so don\'t think it\' s that. The buzzer usually comes on for about a minute then goes away! It does seem like maybe an air bubble or something like that!
I havn\'t done many miles since replacing the faulty AST cap. Could that have led to air being drawn into the system?

Also check the Engine caps not leaking, you can tighten this up a bit by squashing the tabs over SLIGHTLY!! or it won\'t go back on (check the seal inside the cap is not damaged and there is an even circle around the edge where its been sealing)

When you take the Top off the engine side does the water drop or is it already low?

[RedRummy]

Do you have an Aftermarket AST tank? if this is Placed low then you get an air bubble in the Engine filler, it should be the same level or higher.

Really? bugger.  Mine is way lower than the rad cap...  didn\'t think it was aftermarket AST either..

See the piccy below to see the height difference!

PS - sorry for the thread hijack mate!

[RedRummy]

rite i\'ll check both these things tonite! i have a standard ast so don\'t think it\' s that. The buzzer usually comes on for about a minute then goes away! It does seem like maybe an air bubble or something like that!
I havn\'t done many miles since replacing the faulty AST cap. Could that have led to air being drawn into the system?

Also check that the pipe from the AST back to the expansion tank isn\'t crimped or kinked... (or leaking obviously!)

I have the same problem... mine just drinks water, temps always stay fine, andI don\'t get the buzzer, but I keep needing to put water in it... (well, the level in the rad cap is always several inches below the top - just visible in the filler neck and no more)

[Grizzly]

If you take the Engine cap off you\'ll find the level drops, so when you top it up your Atualy over filling the system becouse that water is draining back into the AST.

I was told that the engine Level cap should not be removed to check the level, you should raise the ast and check it from there (to do it Properly) you should check the Overflow bottle Regulaly and change the Antifreeze every year or so but unless you here the Buzzer you should check the engine level every cuple of Months. Sounds messed up but the coolant system needs a Air tight seal to work properly and it will find its own level as long as the caps are Air tight (its how it was designed)

Just keep a close eye on the Overflow bottle if that starts to fall or Rise you may have a problem but in most cases it won\'t change unless you keep toping the engine up.