The radiator cap is an essential part of an upgraded cooling system. Radium caps are engineered to safely improve cooling efficiency by managing the boiling temperature. A higher radiator pressure effectively raises the coolant boiling point, providing an extra safety margin and preventing air pocket cavitation at the water pump.
NOTE: Traditionally, "radiator" caps are mounted to the radiator but can also be found on coolant expansion tanks (below).
Each OEM replacement radiator cap is manufactured from stamped stainless steel for durability. All 18-0076-X1X radiator caps are electroplated black.
Unlike OEM caps which use natural rubber gaskets, these radiator caps feature premium silicone sealing elements for long lasting durability.
PRESSURE
Available with 3 different pressure relief springs: 
1. 1.1Bar (16.0psi)
2. 1.3Bar (18.9psi)
3. 1.5Bar (21.8psi)
TYPES
Radium radiator caps are designed for mini size (32mm ID) radiator necks only. Available in 2 common styles (Type-A and Type-B). 
Please confirm what style your application uses prior to ordering. NOTE: As shown below, Radium Engineering coolant expansion tanks require a Type-A style radiator cap.
COMPATIBILITY
Below are popular vehicles with their respective radiator cap style used from the factory. NOTE: there are many vehicles not listed below.
Type-A
1990-1993 Acura Integra
1991-2005 Acura NSX
1990-1993 Honda Accord
1988-1991 & 2016-up Honda Civic
1988-1991 Honda CRX
1992-2001 Honda Prelude
2003-2008 Infiniti G35
2008-up Infiniti G37
2014-up Infiniti Q50
2014-up Infiniti Q60
1992-2000 Lexus SC400
1990-1995 Mazda Cosmo
1990-2005 Mazda Miata
2006-up Mazda MX-5
1986-2002 Mazda RX-7
2004-2011 Mazda RX-8
1991-1999 Mitsubishi 3000GT
1990-1999 Mitsubishi Eclipse
2002-up Mitsubishi Lancer/EVO
1989-1998 Nissan 180SX
1989-1998 Nissan 200SX
1989-1998 Nissan 240SX
1990-1996 Nissan 300ZX
2003-2009 Nissan 350Z
2009-up Nissan 370Z
1988-1994 Nissan Cefiro
2005-up Nissan Frontier
2009-up Nissan GT-R
1989-2002 Nissan Laurel
1989-2002 Nissan Silvia
1989-2002 Nissan Skyline
2005-2006 Saab 9-2X
1997-up Subaru Forester
1993-up Subaru Impreza
1990-up Subaru Legacy
2015-up Subaru WRX STi
2015-up Subaru WRX
1982-1995 Toyota Celica
1985-1995 Toyota MR2
1986-1992 Toyota Supra
Radium Coolant Expansion Tank
Type-B
1994-2001 Acura Integra
2002-2006 Acura RSX
2004-2008 Acura TSX
1994-1997 Honda Accord
1992-2015 Honda Civic
1993-1997 Honda Del Sol
2003-2011 Honda Element
2007-up Honda Fit
2000-2009 Honda S2000
2008-up Lexus LX570
1998-2005 Lexus IS300
2012-up Scion FR-S
2012-up Subaru BRZ
2012-up Toyota 86
2008-up Toyota Land Cruiser
2008-up Toyota Sequoia
1993-2002 Toyota Supra
2007-up Toyota Tundra
SPECIFICATIONS
Material: Stainless Steel
Sealing Gaskets: Silicone
Pressure: 1.1, 1.3, 1.5 Bar
Design Structure: Type-A, Type-B
Construction: Metal Stamping
Surface Finish: Black Electroplate