I have a 95 M3 79k miles- does it have self adjusting valves? There is a ticking noise that seems to be coming from the front most portion of the cylinder cover sometimes. The ticking builds with the revs. Can it possibly be the oil grade I'm using. I got the 20W50 Mobil Synthetic in there as some people recommended, maybe i should switch to 10W40 next oil change. Are there any additive cleaners that can be used with the engine oil? Maybe I have a sticky valve.