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Been out in car and its pretty hot to say the least, was just looking under the bonnet for something when i heard a tiny hissing sound like air escaping..traced it to the coolent bottle and it sounds like the lid.

Would this be normal as theres nothing leaking from it and its hardly audible unless you put your ear on it or would i require a new seal?

if you've just finished the drive, it's probably the coolant losing heat and contracting..... pulling air back IN to the expansion tank through the little ventilation hole?

ahhh, i see. seems ok now.

The seal on the cap might have gone

leave it go and keep it hot, tel mates new turbo, easy lol

nah its just the radiator cap, when it gets to certain pressure it opens a valve to release some of pressure