Sorry for the stupid question. My coolant level warning came up in the dash. So I opened the reservoir and I cannot see any coolant. I just went and purchased some antifreeze from MBenz which I am going to mix 50/50 with distilled water. My question is where I am supposed to fill it up too. I don’t see any indicator on the tank or inside. Am I suppose to fill it up to where the bottom of the cap would be