flush

I am looking at doing a flush on the coolant in my 2011 E350 CDI BlueEfficiency. Would anyone know how much coolant I would need to get for the system? Mercedes sell them in 5L bottles and I am not sure if I will need 2 or 3. Don't fancy paying for an extra bottle if I don't need it. Kind regards

I have a 1992 200te with about 177000 miles on the clock and I am planning on giving it a quick service this weekend from the looks of it it has not had one for at least 2 years. It has a noisy/tapping lifter on start up and for about 5-10mins after. So I was thinking of using an engine flush to...