Hissing expansion tank

[texastornado]

When I run my 172 up to temp then turn it off my expansion tank hisses!
Is this normal, do I just need to replace the cap or is it an ominous sign ??

 

[Ethan1996]

New cap if its hissing from the cap, coolant gets hot and the gas escapes eventually the coolant will evaporate a bit.

 

[1812lsd]

http://www.cliosport.net/threads/hissing-172.759829/#post-10506228

 

[Ethan1996]

Ah never saw that! At least I was spot on haha.

 

[texastornado]

Ah never saw that! At least I was spot on :wink: haha.

Thanks Ethan, I new to posts and had put it in two places...
But you WERE right, soon as I replaced the cap it was sorted