Make sure you service system at Mercedes-Benz with installed 5.5 engine correctly. For 2009 GL-Class engine it’s necessary to get normal temperature balance. Only exact type of antifreeze will suit Mercedes-Benz GL-Class cooling system. You may use code of motor OM642.822 and volume figure of 3.0 or just tell the 2012 year of production to buy liquid. To maintain cooling system you need 0-0 liters of Green coolant.
A lot of OM642.940 motors are used long in Mercedes-Benz cars but only with good service. To endure car life take only Red antifreeze and pour not more or less than 6.5 liters. It will be advantageous to follow Mercedes-Benz’s rules for 2009 GL-Class service. Use your 5.5 engine longer in 2012 GL-Class by keeping these rules.