Is your radiator loose or rattling around? Such vibration can cause damage to your radiator, which can then cause it to start leaking. We here have seen spinning fan blades puncture radiators, rendering them useless. Replace your mounts with new ones, and feel 'secure' in knowing your radiator is firmly mounted.
The coolant expansion tank provides an buffer for the coolant to 'overflow' to when the cooling system is running. Replace yours with a new one if it is cracked or if there is corrosion inside.
17-11-1-707-505-M9
Coolant Expansion Tank (cap not included), 633CSi (9/82-84), 635CSi (1985-89), M6 (1987-89), Each Brand: Genuine BMW [More Info]
$69.00
Expansion Tank Hoses
17-12-1-119-294-M101
Water Hose for Coolant Expansion Tank, 633CSi (9/82-84), 635CSi (1985-89), Each Brand: Elaplast [More Info]
$3.50
17-12-1-712-736-M203
Breather Hose from Expansion Tank to Breather Pipe, 8 X 13mm (Sold Per Meter), BMW E24 6 Series All, Each Brand: Rein Automotive [More Info]