So I have a C117 2017 CLA45 and the check coolant level came on, don’t think much of it. Heads to dealer because I’m not sure what coolant would be best for it but anywho. I go to add coolant, and something told me to take off the engine cover. There is another coolant reservoir??????? I’m assuming it’s for the turbo or something? But does anyone ever top that up as well?