If the pressure isn't maintained, the coolant can boil and evaporate, putting the engine at risk of overheating.
19045-PAA-A01 NEW Cooling Radiator Cap For 92-2025 Honda Accord Civic Acura RXL
VAICO Radiator Cap for 1986-1987 BMW 325 2.7L L6 - Antifreeze Cooling System hi
VAICO Radiator Cap for 2015 BMW 740Ld xDrive - Antifreeze Cooling System do
MotoRad Radiator Cap for 1998-2001 Chevrolet Metro - Antifreeze Cooling rm
VAICO Radiator Cap for 1997-2000 BMW 528i 2.8L L6 - Antifreeze Cooling vg
Gates Radiator Cap for 2011 Chevrolet Caprice 6.0L V8 - Antifreeze Cooling ne