Simple one, filler cap - Can it be a pressure cap?

[RemarkLima]

As per the subject, I\'ve got a 0.9 bar (12 or 13 psi) cap on the AST as per normal, but my filler solid cap seems to have developed a hairline crack in the rubber ring.

So rather than risk running with it like that, can I use another AST pressure cap on there? I personally can\'t see a problem at all as even if it lifts the spring the coolant can\'t go anywhere but just thought I\'d double check

[arrouk]

yes as even when it opens there in no where for the coolen to go.

matt

[RemarkLima]

Cheers Matt, just what I thought but better check