Originally Posted by Brian77

I just solved the same problem in my '94 e420 that I have had for a few months. Car would start fine but then develop a ticking noise after fully warmed. Changed the plastic camshaft oil tubes located under the valve covers and, as car was due for an oil change, switched to a 5w-40 fully synthetic oil (I believe that MB recommended a 15w-40 mineral oil and no clue about what car had in it before). Your camshaft lubrication setup may or may not differ because your car has a different engine. Have heard that oil additives with silicone can do more harm than good because they block oil passages. Good luck.