Billet Aluminum Coolant Cap

BMW isn't known to have the most robust coolant systems, but most of this can be fixed with regular preventative maintenance.  If you want to take your system a little farther, look no further.  This billet aluminum coolant reservoir cap from German Auto Solutions is the perfect accessory for your build.  They take one piece of billet aluminum, CNC it down, and attach it to an OEM BMW internals.  This cap vents at 1.2 bar, unlike the OEM one which is 2.0 bar. This limits the maximum internal coolant pressure to 1.2 bar (17.5 psi) instead of the OEM spec of 2.0 bar (29 psi). Even something as simple as overfilling the coolant recovery tank a little higher than the recommended level will result in potentially damaging pressures when using the stock 2.0 bar cap.

The German Auto Solutions 1.2 bar coolant cap fits many BMW models manufactured from 1982 to the present. Use the application list tab above to verify fitment for your vehicle.