BMW k 1200 rs Repair Manual page 190

Excessive loss of coolant.
Check coolant circuit. Coolant circuit is inter-
rupted
Engine remains cold or warms up very slowly.
Check thermostat. Thermostat does not close.
Are both radiators equally warm and the cool-
ant hose to the water pump cold?
yes
Repair the fault.
yes
Replace thermostat.
17.13