How do you add top off coolant to Mercedes GL450?

To add coolant to a Mercedes GL450, first ensure the engine is cool and locate the coolant reservoir, typically found near the front of the engine bay. Remove the cap and check the coolant level; if it's low, use a 50/50 mixture of the recommended coolant and distilled water. Carefully pour the coolant into the reservoir until it reaches the appropriate level, then securely replace the cap. Always consult your owner's manual for specific coolant type and procedures.