briandavis06

Guys/gals I’m asking for some suggestions for what this tapping noise is on my M156. Each video is very short. Car is a E63 so I’m going to repost there but due to volume of M156 knowledge here I appreciate you allowing me to ask for help.

This loud tapping happens only at idle engine speeds at full operating temp in warm weather and only after going low city speeds for 10-15 mins (presumably oil is at its thinnest and aux cooler has not gotten much airflow). A/C off in all videos.

I just replaced tensioner belt and idler pullies; this noise is not RPM-related and consistent like the tensioner and idler noises. No sound at cold start at all. Quiet as a mouse. Sound only develops at operating temperature after driving around town at lower speeds in warmer outdoor temps with some stop and go. Noise presents with highest operating temperature then will go away with RPM.

I had oil changed yesterday and ran through a filter with no metal shavings of any kind found. I drove it 2 hours home by highway on faith and it never lost power, no CEL light or workshop errors, misfires, anything. This car has been rock solid for me for about 3 years. Currently 179k miles.

it is time for a timing chain and oil pump chain I fear. What does everyone think?

THANK YOU ALL!!

hachiroku

cam adjuster is my guess. you're at 179k...i'm at 152k and sometimes get that noise. i also have gotten cam adjuster intake over advanced. i've replaced my lifters twice and have had my head studs done twice. no report of chain or tension issues.

briandavis06

Thank you for your feedback. I’m unsure if head bolts or any valve train components have ever been replaced before my ownership but the VMI didn’t show them - it was executive owned, highway driven, and dealer maintained religiously before me which is the only reason I felt confident and bought it.

go team

From what I’ve seen timing chains don’t go. Most feedback I’ve received has also been the same. One bank is maybe a degree off timing from chain stretch. Timing chains aren’t really a thing anywhere as near as the Audi V8’s.

Solo wing

Sounds like the adjusters are not locking anymore. You can read the camshaft timing using a diagnostic tool or remove the valve covers and check the if the adjusters are locking or not using a wrench.

hachiroku

if in fact they are your adjusters which i do think they are...you'll get back some lost HP. over the past few months i feel like i've lost 20-30hp in certain parts of the rpm range. also, i've just been resetting any cam adjuster codes because i like to live life dangerously.

i did pick up a set of used cam adjusters with 80k on the clock. I plan to rebuild them with the nice custom parts available now. you can find more information on instagram at @63everything as well as on youtube. they should last much longer than the OEM units.