Coolant Buzzer :(

[alexb]

Had a bit of a worrying drive tonight... Started the rex to take the new missus back from the cinema (go see Sin City, it\'s ace!) and the add coolant buzzer comes on. God it\'s loud!

The needle on the gauge was right at the bottom while the buzzer was on. I stopped the engine, opened the coolant filler cap (the centre one) and I could stick my finger down it and not get it wet (oo-er!). No coolant on the ground though.

Restarted the car, buzzer and light on again, needle at the bottom of the gauge. While driving (very gingerly) out of the car park the light and buzzer go out, and the temp needle climbs up to normal level but no higher... (I know the gauge isn\'t particularly accurate tho)

Luckily it\'s a shortish drive back so I drove as gently as possible. Back at hers I added about 500ml of water and when starting the car to drive home no buzzer and normal temp level...

Having done a bit of reading up I\'ve got a plan of action for the morning: Firstly, I\'ll start the engine with the filler cap off to check for bubble and an indication of knackered water seals, and then do a full coolant flush and re-fill.  

Then I\'ll be booking the car in to Jimmy\'s so I can get the coolant system checked out properly pressure and CO2-wise. It\'s done about 62k so it\'s going to be rebuild time sooner or later...

Cheers,
Alex

[Oedipus Rex]

maybe you were just low on coolant, it does go slowly. I need to fill mine every couple of months.

[andrewrx7]

Plus the AST cap will need replacing sooner or later. You will loose coolant into the overflow tank when the car gets hot, and draw it back again when the block cools. The cap is sprung loaded with a rubber flap, and they do stop working at times. Thus you loose coolant to the overflow, but it does not get drawn back. You then seem to below on engine coolant. Might be worth changing the cap as a matter of course, to?

[alexb]

Thanks guys, hopefully it was just a \'normal\' low coolant situation. There was none in the overflow tank behind the headlight though. I presume I can get a new AST cap in Halfrauds?

Just having a cup of tea then out to see what\'s up...

Cheers,
Alex

[andrewrx7]

Originally posted by alexb
Thanks guys, hopefully it was just a \'normal\' low coolant situation. There was none in the overflow tank behind the headlight though. I presume I can get a new AST cap in Halfrauds?

Just having a cup of tea then out to see what\'s up...

Cheers,
Alex

As far as I\'m aware, its a Mazda only part. (or one of the rotary garages - reworx, rxmotors etc)

[sdminus]

Alex.
I got mine from Wilco for 6 quid. Mazda wanted over 20 quid !!!!!!!!!!!

[alexb]

Cheers for the tip Scott!!

Alex

[alexb]

Hmm, well after draining and re-filling the system i\'ve been having to put in a cupful or so of water every day, and the overflow tank is getting fuller...

So I don\'t think there\'s any more air in the system creating more space for coolant to be added, which means it\'s being pushed into the overflow tank.

Should changing the rad and AST caps be the next step? Just now I went outside and started it with the rad cap off, the coolant was about 2" below the top (filled to brim earlier this evening then popped to the supermarket), as the engine was running the coolant rose towards the top of the filler neck and I could see there was a small stream of tiny bubbles... I couldn\'t smell exhaust, and there was no white smoke or anything in the exhaust (but then I\'ve read on nopistons.com that you can tell which part of the cycle the seals have gone on depending if you see smoke or champagne bubbles). I\'m hoping the bubbles were due to air in the system rather than exhaust gas, but it\'s been 2 weeks or so since I re-filled it so it can\'t still be that can it?

I suppose the next thing after changing the caps would be pressure or hydrocarbon-testing the coolant, could any garage do that? Jimmy\'s don\'t have the equipment so is the Mazda dealer worth a shot?!

Finally, if it is the seals then is it worth getting a rebuild sooner rather than later? It\'d be a bitch to pay for it now but if it\'s going to be cheaper in terms of less damage having been done I\'d rather not run it until it goes pop...

Any advice from the experienced bods on here greatly appreciated!

Cheers,
Alex

[sdminus]

Alex.

Can you hear any air in the cooling system when u switch the car off ?
what is the oil looking like?
Does the car dump coolant out of the over flow?
I there any smoke form the exhaust and if so what colour is it?
Do the main coolant pipes get hard when the car is up to temp?
Do you have a water temp gauge other than the stock one?

Scott

[alexb]

Alex.

Can you hear any air in the cooling system when u switch the car off ?
what is the oil looking like?
Does the car dump coolant out of the over flow?
I there any smoke form the exhaust and if so what colour is it?
Do the main coolant pipes get hard when the car is up to temp?
Do you have a water temp gauge other than the stock one?

Scott

Hi mate,

Ok, to answer your questions:

1) no, sounds like normal cooling down noises, can\'t hear any gurgling or boiling noises
2)Oil\'s ok, done about 2k miles on current plus I topped it up last fortnight.
3) No, but it has been increasing the volume in there since I\'ve been adding the water as I\'d filled it to the full mark on the dipstick when doing the coolant replacement. I\'m sure it\'d overflow if I kept adding....
4) Only a puff of oil smoke at startup, after that it\'s fine.
5) Hmm, not checked. Is this to check for pressure? The system does get pressurised when warm, also tried Andrew from Jimmy\'s tip of running the engine for 2 mins from cold then taking off the rad cap to see if there\'s pressure in the cold water i.e. pressurised by exhaust not by heating. It did do it last week, thought it might have been excess air in the system tho, will test again tomorrow.
6) No, unfortunately not. I know the stock gauge is pants...

Hope this gives some pointers mate

Cheers,
Alex

[Carl]

When the car is cold the coolant should be a couple of inches down the filler neck,not to the top.
Also I strongly reccomend that you use only a genuine Mazda AST cap.0.9kg (13lb) is the right one.
Regards
Carl

[framey]

What would be the  signifigance of the coolant being full to the top of the neck - like a little spliis out when you take the cap off (totally cold).

Thanks

[alexb]

When the car is cold the coolant should be a couple of inches down the filler neck,not to the top.
Also I strongly reccomend that you use only a genuine Mazda AST cap.0.9kg (13lb) is the right one.
Regards
Carl

Cool, thanks for the advice Carl.

Cheers,
Alex

[the lemster]

there has been several mentions in other posts about the expansion tank...

I unbderstand why it is there... and just wondered if it was wise or usual practise to ahve any level of fluid in there...

when hot and the system is presurised and the expansion takn is in use... and if the system has a slight leak somewhere... wheh cold it will draw extra water into the system from the extra in the expansion tank...

does that make sense and if so what sort of level...  seems odd to ahve a dipstick and not have any fluid in there apart from expansion overflow?...

[alexb]

What would be the  signifigance of the coolant being full to the top of the neck - like a little spliis out when you take the cap off (totally cold).

Thanks

Presumably as the engine reaches temperature the excess would just flow into the expansion tank, part of the normal design.