Originally Posted By Digimap
Not sure of my physics here, but doesn't water boil at a lower temperature the lower the pressure?
How high were the passes you were driving over? oldgit

High-altitude cooking is the opposite of pressure cooking in that the boiling point of water is lower at higher altitudes due to the decreased air pressure.


This should make no difference as the system is pressurised and therefore not affected by the atmosphric pressure.
Perhaps the cap is faulty releasing the pressure too early and with the slightly lower atmospheric pressure vented.

New caps are cheap and an easy fix.

JohnV6
2022 CX Plus Four
2025 Renault Scenic Alpine etech "Yvette"