I tried one of these on my 560 SEL. It did not fit. However, a different brand may work on a different model of Benz. I used an overhead cam valve spring compression tool. Not available at the five parts store I tried, ended up buying it at a tool store (KD brand). Sorry it does not have a part number on it. The price was about $40.
My double spring valves were strong causing the tool to bend. I just kept wrapping it with duct tape to keep the feet together. I hope this helps.
1988 560SEL, Green, Chrome wheels.
2000 Suburban, 20" wheels, DVD, wood grain dash (wife's car).
67 Beetle euro, Lots of Empi parts.
69 Beetle conv, 1980s cal look.