Radiator Cap Pressure rating

[foxfan1992]

So, forgive me for my 'noobness' here, but here's my situation.

I just bought a Mr Gasket radiator cap with a temperature gauge on it - this one here: http://www.autopartswarehouse.com/image ... 475s_1.jpg which is rated at 7psi. What I'm worried is that I might have bought a radiator cap with a pressure rating too low, since I cannot see what my current and worn out radiator cap's pressure rating is. I don't exactly want to blow up a $40 radiator cap just because the rating is too low. What do I do?

[flinterman2000]

You need a 9lb cap. Also make sure you use the right anti freeze.

[foxfan1992]

You need a 9lb cap. Also make sure you use the right anti freeze.

Drat... then I'll have to return the radiator cap and get another one.
Also... I've been using 50/50 antifreeze since my radiator has aluminum components that will corrode - and I live in a temperate climate where the temperature rarely exceeds 30C and -10C.