when you replace the chain guides you should replace the chain too.
you don't have to disassemble the engine for this, but this is a big hard job with lots of details and work. and no room for mistakes. this requires experince and knowledge of the motor.
Most of the time when a code is stored it's usually for the variable valve timing solenoid
not the chain.
Hello again. I have done this job quite few times I wasn't aware that your a tech. But even though this is a much harder task even for techs that have no foreign car experience
as for the chain I have not heard about replacing the guides alone I think that would be
a waste of time, specially when you say there is a rattle. Your a tech would you replace the guides on a gm motor and leave the chain. To me I think not.
AS far as communication with BMW tech I am willing to give you all the advise and help
but if your looking for step by step question answer on the removal, that I couldn't do. I could send you the removal instructions if you'd like.
If you want me help please reply, If you'd like me to opt out and have another BMW tech
help I will too. I just want to see get the help you need so you can get going.
For rails you will have to remove the front cover ,generally these last fairly well into the life of the motor.Unless it' s of course been neglected.
But if your more after noises ,the vanos units themselves will give a low level knock sound when stuck,and sometime a fault which you indicate you have a timing reference fault.may indicate a need for that vanos
Then you'll need all the lock blocks and locater's
But look into the oil cap (if you haven't disassembled yet ) see if this is sludged over
Another indicator (quick) is remove the oil filter,if you see metal then the Bakelite is blown off the rails.
if that looks good ,oddly enough check the plugs when they are loose you get some odd noises like the cam is broke
for the timing fault move the intake cam sensor (swap them) see if it follows it ,they frequently go bad,( I'm only familiar with the BMW software codes so any other won't help me)
Hope this helps
Good luck with your project