German Auto Solutions Billet Aluminum 1.2 Bar BMW Coolant Cap

Reduce unnecessary stress on your BMW's aging cooling system with the German Auto Solutions 1.2 Bar Billet Aluminum Coolant Cap.

Many BMWs manufactured from the 1980s through the mid-2000s were originally equipped with a 2.0 bar (29 PSI) cooling system cap. While this higher pressure raises the coolant's boiling point, it also places additional stress on the plastic expansion tanks, radiator end tanks, thermostat housings, hoses, and other cooling system components that become brittle with age and repeated heat cycles.

German Auto Solutions developed this cap to reduce maximum cooling system pressure to 1.2 bar (17.5 PSI). After extensive research and testing, G.A.S. determined that 1.2 bar provides sufficient pressure to maintain proper cooling system operation while reducing the maximum pressure placed on aging components.

Product Features

• 1.2 Bar / 17.5 PSI pressure rating
• Replaces applicable factory 2.0 Bar / 29 PSI caps
• Helps reduce stress on plastic cooling system components
• CNC-machined from 6061 billet aluminum
• Anodized finish for corrosion resistance
• Laser-etched pressure rating and German Auto Solutions branding
• Uses Genuine BMW internal components
• Internals recalibrated by German Auto Solutions to 1.2 bar
• Functional cooling system upgrade and engine bay dress-up piece
• Designed and manufactured by German Auto Solutions

Why Lower the Cooling System Pressure?

BMW cooling systems are well known for plastic components that can become brittle as they age. A sudden failure of an expansion tank, radiator tank, hose connection, or thermostat housing can quickly result in coolant loss and engine overheating.

The G.A.S. cap reduces maximum system pressure from approximately 29 PSI to 17.5 PSI, helping reduce the load placed on these aging components.

The 1.2 bar pressure setting is still high enough to maintain the cooling system's intended operating characteristics under normal conditions, with G.A.S. testing indicating OEM pressure requirements are maintained up to approximately 126°C / 260°F.

Important Note

A lower-pressure cap cannot prevent every cooling system failure. Old, cracked, damaged, or deteriorated components can still fail even at normal operating pressure.

This cap should be considered additional protection, not a substitute for proper cooling system maintenance. Worn expansion tanks, radiators, hoses, water pumps, and other components should still be replaced as necessary.

Replaces / Cross-References BMW Part Numbers

• 17110152374
• 17111742231
• 17117639022

A Simple Cooling System Upgrade

For BMWs still using the original-style 2.0 bar cap, the German Auto Solutions 1.2 bar cap provides a simple way to reduce maximum cooling system pressure while adding a high-quality billet component to the engine bay.

If your coolant cap is more than five years old, replacing it during routine cooling system maintenance is also a good preventative-maintenance practice.

BMW Fitment Guide

*Fitment on later BMW chassis varies by engine, production date, and cooling-system configuration. BMW catalogs show the current 17117639022 cap extending into later F-series applications, so I would not advertise every F-series BMW as compatible without VIN verification.