How to change coolant BMW i735 1990?
To change the coolant in a 1990 BMW i735, start by ensuring the engine is cool, then locate the drain plug on the radiator and position a container underneath to catch the old coolant. Open the drain plug to let the old coolant drain out completely. After draining, close the plug, and refill the system with a 50/50 mixture of BMW-approved coolant and distilled water through the expansion tank. Finally, run the engine for a few minutes to allow the new coolant to circulate, and check for any leaks before properly disposing of the old coolant.