Checking pressure drop in cooling system
WARNING: This page is about a different car, the 2011 BMW Z4, 2010 BMW Z4, and 2009 BMW Z4. However, it is still accessible from the selected car via links, so may be relevant.
Open cap on coolant expansion tank. Fit special tools (1) 17 0 101 and (2) 17 0 113.
Build up GAUGE PRESSURE and wait approx. 2 minutes.
Cooling system is impervious to leaks if pressure drop is max. 0.1 bar.