Welcome back Tom, what do you run in your 108 4.5? Synthetic oils in Vintage MB's is a subject that hardlly gets covered here. Am certain it will slip right past primitive engine seals on 111's. Old timers awhile ago cautioned me against running synthetic in my 114. Yet it worked well in my 116 twincam 2.8 last Summer, seeming to make the engine run quieter.