Boiling?!

[spagram]

Ok, got home today and parked up, all was normal. came out a few mins later and i could hear what sounded like a kettle boiling under my bonnet! had a look underneath, the black plastic reservoir thing was hissing quite loudly and the boiling sound was coming from all across the front of the car. i put the ignition on to check engine temp and the warning buzzer came on, engine temp was normal though. Checked the dipstick which had plenty in it.
Any ideas? im planning on a rebuild next month anyway but it\'d be nice if i could drive it to rx motors (about 100miles away).
cheers
stuart

[Oedipus Rex]

Disclaimer: I am far from an FD expert.




sounds to me like the systems not pressurising and allowing the water to boil.

If the AST was hissing I would hazard a guess that the rubber seal on the AST cap has corroded.

[spagram]

any ideas what what cause it to not presurise? will check the seal on the ast.
cheers
stuart

[spagram]

Right, yes the seal on the ast cap is split, would this stop the system from pressurising?
Where can i get a new cap from, Mazda?

[Spotlamp]

Any leak in the cooling system will prevent it from pressurising, whether it\'s a hose off or a split seal in a cap.

Replacements can be bought from Mazda or I suspect any of the vendors listed at the top of the page.

HTH
H

[Tintin]

In my opinion you\'d be better off replacing the AST with an aftermarket one coz if the actual AST splits you could do serious damage to your newly rebuilt engine

[MillSpeed]

This boiling seems to be quite common on FD\'s, even with a healthy AST cap. I replaced the 0.9bar cap with a 1.1bar cap off a 1.8 Mazda 626 and this seems to have cured the boiling problem. It was something like £4.50 from a motor factors, much better than the £18 mazda tried to charge me! Personally I\'d eliminate the AST altogether and run an FC coolant filler neck.

[spagram]

Cheers guys, i think ill get one of the 1.1bar caps off a 1.8 Mazda 626 for now then replace the ast when the engines rebuilt.