Originally Posted by Mercenary(FH)
how much do valves adjustments cost?
The valves are not adjustable on the E36. According to Bentley, the M44 engine uses hydraulic valve adjusters (HVA) with rocker arms, and the M42 & 6cyl engines use hydraulic cam followers. Both systems are self adjusting and require no maintenance. It's normal for tapping to occur at startup for these systems, but if the tapping persists after 10-15min, then the HVA or follower needs replacement, which means removing the camshaft first
For the E30, here's a nice writeup from Pelican: