CUSCO High pressure radiator caps (1.3 bar) now available from us! $50 each
Radiator caps are designed to vent excess pressure build up in a radiator system.
Pressure builds when coolant begins to boil. The radiator caps act as a ‘safety valve’ so that the excess pressure built up will not blow a radiator hose or even the radiator itself.
The factory supplied radiator caps for most cars holds up to 1 -1.1 bar of pressure. However, once the pressure has been released, in most cars, a quick chain reaction follows where the remaining coolant begins to turn into steam, because of the pressure release, which in turn causes the radiator cap to continue to vent steam. This cycle only stops when the engine is shut down and allowed to cool completely. Head gasket failures are often caused by overheated coolant.
High pressure radiator caps like those from CUSCO allow a higher pressure build up, giving the driver just a wider pressure margin before the cap vents its pressure. The increased pressure also increases the boiling point of the coolant. We have found the margin is often just enough to prevent a serious overheating of the engine.
However, if your car is frequently overheating and venting coolant (evidenced by dried coolant stains around the radiator cap/radiator/expansion tank), we would recommend first to upgrade the cooling system, with a larger radiator or better fans or waterpump or clearing the air channels behind the radiator for better air flow.
HONDA CIVIC all years
HONDA INTEGRA all years
MAZDA MX5 NA / NB / NC
many other applications