It's the fan shroud that blocks access on my car. You could take it loose, but you can't remove it without taking off the fan. I take the fan off by unfastening the shroud and orienting in such a way to gain some room to get to the fan screws. Once the fan and shroud are removed you have six inches of space between the engine and the radiator. But it's not worth all that for a valve adjustment. I suspect other years and Euro versions may have had different fan shrouds????

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1976 240D
1987 560SL
2007 E320 Bluetec
1998 C280 (now son’s car)
1982 240D Manual - Sold