Don't frequent the 320i section that oftern but here are 2 cars we've had this week. Both cars had cam shaft / crank shaft corrolation faults (which we have seen numerious times)
Apart from the numerious misfire codes usually assoicated with plugs and colis these issus are now becoming alarmingly normal. The fix is usually top guide, main chain guide, a new tensioner and 2 vanos bolts anda new rocker cover gasket, which including VAT is around £200 in parts plus labour. Once done the first one in these pictures was cured.
you can see pre work on these pictures how slack the chain was. The tensioner was lose and was also weeping oil (again we've seen a fair few of these engines with this issue) the car in question was a pre LCI 320i N46 engine with just over 70k on the clock.
The one below will concentrate the mind.
A late 09 plate 320i again cam shaft /crank shaft corrolation fault this car also had a misfire issue but something wasn't right the car had service history and recoreded at just under 33k on the clock folowing BMW's service agenda, servicng by BMW plus another garage engine in question was from memory an N43
The above is frightening. We never expected to see the above. All I'll say is we are seeing these engine coming through with cam shaft /crank shaft related faults nad of ocurse misfires etc. Oil wise the rules from where I stand are clear.
1/ CBS intervals are too long some cars that cover low mileages can have oil in the sump for over 2 years with ease (as seen above) low mileage for some cars means less care less visits as the CBS data rules.
2/ change oil every year. If you do 3100 milea a year change the oil every year.
3/ hear a rattle something doesn't sound right get it in front of someone who understands the breed. As we've discovered most "average garages" don't sounds harsh but these engine appear to be very delicate.