COOLANT LOSS DETECTION KIT

[Barnet Al]

I feel sure you are right Haydn, if there is no overflow it can not matter if the cap has a pressure release or not. If there is an overflow it could presumably be sealed off.
The question is why is the label written in 3 languages on a vehicle intended solely for the Japanese market, the answer must be that for reasons of economy Mazda use parts shared with other vehicles.
Alan