1 My '06 M Roadster had 52K on the clock and had been trouble-free until April, 2012 when I took it into the dealer for some routine maintenance. The service advisor called me and said the techs thought my engine was a bit "too noisy".... uh oh, I know what that might mean and so did they. That coupled with the fact that cold start and idle was a bit rough pointed at the VANOS. I checked my service records and I had had the cam bolts checked at Inspection I, but not at Inspection II which was 2 years prior, in 2010.
Anyway, valve cover off and the cam bolts are indeed loose as seen from the rear. Luckily no bolt fragments seem to be missing and all looks clean inside. I took some photos, but not much to see at this point. Solenoid seems okay and no fault codes have been thrown. Of course won't know the full story until the vanos is completely apart. Similar to other people's reports, the parts come out at approx $100 with 7 hours labor, so at dealer rates somewhere around $1K+ with tax.
2 View from the rear to the front of the engine, showing the back side of the VANOS cam gears. Left side is the intake VANOS and the right side is the exhaust VANOS. Can definitely feel the loose intake bolts.
Just before the 4 year factory warranty expired, I decided to purchase an extended one through the dealer and went with a 3rd party called Warranty Solutions. I almost never buy extended warranties on anything, but I had had 2 ABS module failures, the fuel pump wiring SIB, and loose engine mounts which gave me some concern for the future. My BMW service advisor spoke with the warranty company and they are covering the entire repair minus the $50 deductible. Needless to say, I am very happy that 1) we caught the problem before any catastrophic damage to the engine, 2) my wallet is a little fuller than I anticipated when the story began.
3 So, here are the damaged intake cam bolts that were removed. You can see that one was completely sheared in two and the others were all in various stages of self-destruction. No damage was found to the exhaust cam bolts, but those were replaced as well. The BMW replacement bolts are definitely different than the originals, so clearly they reformulated the design after the many reports of S54 ///M VANOS failures.