as far as I know, the original reason pressurized caps were used is to prevent boilover when the engine was shut down due to heat soak back. Now they may actually run at over 212°. (I'm not so really up on the small details of modern engines, I have never had any even begin to fail in the last 20 years) I even run my mustang with no pressure (I'm afraid of that 40 year old radiator.) And I don't drink coffee, and water with anti freeze doesn't boil at 212°. Unless of course you aren't using antifreeze, in which case I don't want to talk to you. But what ever the case, these engines don't need them.
