How to Add Coolant to a 2003 BMWby Lynndee Marooney
Coolant, also commonly referred to as antifreeze, is a critical component of the BMW's cooling system. Coolant is used in all automobiles to absorb the heat from the engine. Without coolant, a vehicle quickly overheats and causes damage to the engine. BMWs manufactured after 1970 do not have the ability to add coolant through the radiator cap; instead, you must add the coolant to the reservoir.
Lift the hood and locate the coolant reservoir. The reservoir should be near the radiator and you should see coolant in the reservoir. Coolant is generally green in color, but in some cases it is red. Look for a hose coming out of the reservoir and into the radiator to ensure you have the correct reservoir.
Remove the cap. If the cap is a pressurized lid, do not remove it while the engine is hot. A plastic flip-top tab is most common and is not pressurized.
Insert the funnel into the opening and pour the coolant into the reservoir until it reaches the "Full" line. Do not add water into the BMW reservoir; use only the antifreeze. If the coolant was very low, run the vehicle and recheck the levels after the coolant has been drawn into the system.