Example: As a result of a hydrometer measurement on a 318i engine manufactured before August 1987, it was found that frost protection down to -10°C is provided. In this case, it is necessary to drain 2 liters of coolant and add 2 liters of pure concentrate.
Close the radiator cap and after a test drive recheck the frost resistance of the fluid.
The original entry can be found on the portal: BMWMAN