I just bought a 2003 Audi A6 4.2 with 55000 miles on it. The car runs great but there is a tapping noise that comes from the engine that sounds like lifters. The local dealer changed the oil in the car with w5-40 castrol syntethic but the noise is still there. It is not a loud noise but its just bugging me. Any idea? Please help

 

I would use 0W/30 oil full synthetic in that baby and it could be injectors tapping best way to test this theory is with a stick from your ear to the offending noise or mechanics stethoscope with allows you to probe where the sound is and if it is the injectors then use some fuel cleaner through the system

 

Thanks for the info. I have been to the dealer but they said the noise is normal but when I showed the car to an independent audi shop they said that it could be low oil pressure due to screen on the oil pump being clogged up. Another shop said is the injectors not the lifters and its normal on all 4.2s. I don't know what to think anymore. This sound is more like a loud ticking noise rather than tap.