My 2010 with 11500 miles is starting to rattle too much after it gets warmed up. I want to replace the chain tensioner but need someone to walk me though it please. I have a choice between replacing it with an aftermarket fixed unit or stock BMW tensioner and could use some feed back. It's about even money to do either and I want to do the labor myself..
my 2010 was making a tremendous racket. i, and the dealer thought it was the cam chain tensioner. when i picked it up, it turned out to be the header, which they replaces, of course under warranty. i asked about the cam chain tensioner failure, to which they replied they have never had one come in. this is a big high volume bmw (only) dealership. nice and quiet now.
Not much to go wrong with the stock one unless the check valve fails or loses a lot of oil pressure for some reason. On the BMW K1200GT when the hydraulic one collapses due to lack of oil pressure it pretty much craters the upper valve train to around $5,000 to $13,000 in damages. BMW came out with about 3 iterations of the hydraulic, spring, whatevers, and finally decided some chain guard anti-jump flimsy plastic thing was in order. APE made a manual to address it. There were a lot of cam chain jumps on that model over the S which seems very rare to jump.
Here is something on the manual APE one I installed in the S. Mine goes out of warranty in 5 more months so I'm not sweating it (I'd put the old one back in should I need to take it in for something BMW would squawk about.). It quieted it down a lot and idles much smoother too.
mine is making that noise also and it's the header not the cam chain. The good way to check is take a stethoscope and put it up around the motor and you won't hear the noise touch the header all the way up by the oil filter and then you'll hear it.