Hey S2ki-ers,

I am modifying an s2carbonworks overflow tank that I bought used here from another member and now have finished the modifications I'm able to do. The tank didnt fit off-the-bat so I went to town with a dremel and metal file and made the necessary mods. Now I need to patch the hole I created and was wondering if anyone knew the max psi the tank needed to withstand.
What does the OEM plastic overflow tank withstand? I know the radiator cap on the radiator says "1.1 bar" which is equivalent to ~16psi but I was wondering if the tank needed to be that strong too. Let me now. Thanks.

 

I don't believe the coolant overflow tank is pressurized.

 

I know this tank has to be pressurized to at least 4psi. If you disconnected the hose from the radiator immediately after you turned the car off, obviously radiator fluid would spill out due to the pressurization. Knowing this, some of that pressure is being contained/transferred to the overflow tank. This is pretty basic/common knowledge to me at least.
Does anyone have any more knowledge or expertise is this area?

 

The cap is pressurized not the overflow. The cap opens at a certain PSI range and fluid is forced into the over flow. If you remove the cap yes fluid would come out but if you removed the hose going to the overflow, nothing would happen until the cap opened. If our cars operated with a system without a radiator cap, then yes it would be pressurized.

 

agreed...the overflow tank itself is not pressurized...just seal the tank with good quality plastic epoxy