Greddy Radiator Seal Cap Black + HPS Silicone Cap Black + Clamp Combo

Aluminum Radiator EJ Turbo Subarus do not need two distinct pressure caps.

The Radiator Cap Debacle of the past 20 yrs has a solution.

Remove the pressure cap from the radiator, it can be done a couple ways.

Easiest way is to buy this combo here.

Either with one silicone cap and clamp for a custom over flow setup, or two if you’re keeping the stock overflow.

Hard way is to weld on a different style threaded cap that’s not pressure based. Welding, fabricating, etc are nice when you have the time.

This combo is inexpensive and gets the same thing done.

Running a solid cap on the radiator will also allow a higher pressure 2 way cap on the expansion tank to increase overall system pressure. 1.3kg/cm² or 1.5kg/cm² is common. 1.3kg/cm² is available from Greddy that matches this combo (link here). Radium sells a Black 1.3kg/cm² or 1.5kg/cm² that is close (link here).

I’m going to do a write up on the website here about radiator caps, I’ll link it here when it’s ready.