Differences between radiator caps

[b3h3m07h]

the other day i bought a new radiator cap because the one i had was a little old and the spring tension was a bit weak. when i went to install it i noticed the new one only had one rubber seal not two like the old one, one for sealing the cooling system and the other just under the shell of the cap to seal it up the top. has anyone come across this themselves and will it make a difference?

[hako]

If it's only got the one seal that keeps the pressure in the result will be that coolant will not be sucked back into the radiator from the header/overflow tank. Also there will be a bit of leakage around the cap. I'd replace it pretty soon.

[b3h3m07h]

well its kinda got a seal but its just a metal plate that would apply pressure to the top of the radiator. the cap is rated at the same pressure but do commodore caps differ?