pauliehcfr

you say you did an oil change and added 6.9l which is about right. BMW 6 cylinder engines typically take 7 quarts of oil. if the vehicle has been sitting for 2 years without being driven, that could be part of the problem. how much have you driven the car since it was put back on the road? usually a good hard drive will help deliver oil to components that may be sticking and help free them up

turbogate

I think I have the same issue. Does the noise completly go away when you switch the AC on? Mine completly goes away when compressor is running. It seems to point to the compresor/pulley maybe? When the compresor is under load (meaning engaged) there's no more noise. Mine sounds like a diesel engine at idle, mostly when it's cold. Sooner79 might be on to something as well.

my_galaxy

thanks guys
i am going to put it on the road in couple days and i will have it inspected.
actually i am going to plate it tommorow and will start driving it. my main concern was that i dont want to damage the engine.

-thanks for your help. ONCE I FOUND OUT THE PROBLEM, I WILL UPDATE IT FOR YOUR KNOWLEDGE
THANKS

my_galaxy

OK GUYS PROBLEMS BEEN FIXED
it was problem with the fuel. either previous owner used regular fuel or fuel was too low in the tank (only 30 miles worth of fuel)
either way when i filled it up with premium 91 , knocking sound just disapear.
-ALSO AS PER OWNERS MANUAL, IF ITS ALMOST EMPTY (LESS THAN 50MILES) IT CAN CAUSE SERIOUS DAMAGE TO THE ENGINE
THANKS FOR YOUR HELP

one4thethumb

The "tapping" is endemic for the 2006 530's. I regularly encounter the problem when it is below freezing and I take a short drive to the club for my early AM workout (less than 1 mile). The engine doesn't tap when I leave the garage and head to the club, but the act of driving it a short distance and then letting it sit for approx. 2 hours before heading to work. I stop for coffee, leave the engine on, and I hear the tap. When the car is warmed up and has been run for approx. 5 miles, the tap disappears.

BMW had a fix, a re-engineered head that permitted a smoother flow of motor oil to prevent the tapping, but was advised by my SA that due to the exorbitant cost of the fix ($5K - $7.5 K USD) it was either abandoned or is now the fix of last resort.