totally never realised but when i did water bypass today i noticed the new rad cap i had supplied with my new hiflow radiator was a 1.3kg/cm2 which is making wonder if that higher pressure caused my water leak so i have now put on a stock cap 1.1kg/cm2 but as this was off my old rad i need a new one but all i can find is 13psi caps are these the right pressure?

Hi Kev,

 

The reason that hi-flow radiators use a higher pressure radiator cap is so that the coolant can reach higher temperatures before it "boils" (the higher the pressure, the higher the boiling point of a liquid).

 

Stock radiator cap: 1.1kg/cm2 = 15.6psi

Hi-flow radiator cap: 1.3kg/cm2 = 18.5psi

 

13psi = 0.9km/cm2, so therefore not high enough pressure.

 

I believe you can get the correct 1.1kg/cm2 radiator caps from MJP in the traders section.

 

Having said that, your hi-flow radiator will work best at 1.3kg/cm2.

 

HTH

 

Regards,

brilliant thanks dan was a little concerned with pressure as one of the pipes under the plenum failed on the weekend so had to do a water bypass (still got drivers side to do) i have however fitted the 1.1kg/cm2 rad cap on for now till i get to do the other side so hopefully i wont pop anymore pipes (so far so good lol)