TTMBCLS

Need help identifying noise in my engine.. 35 seconds in the video. I have identify a different sound. It is a rattling sound coming from the middle of the left engine. I think it is a fuel throttle body?

GLENN S.

Sounds like a valve train noise, narrowing it down may be difficult

TTMBCLS

the sound slightly went away with oil additives but im guessing its an injector noise. the noise you can barely hear it on youtube but its more of a hallow tap.

TTMBCLS

updated the video. The noise is coming from top left of the engine. What can this be? my guess is the intake cam. or the camshaft adjuster or timing chain?

TTMBCLS

could this be a bent valve?

irushaud

This is a very common issue of new generation v8 engines. Mercedes tips document as follows.

Ticking or pulsing noise from high-pressure pump and fuel injectors -

Design group
07.02 Injection pump, unit pump, high pressure pump
Date
12-15-2014
Validity
All engines 276 / 278 / 157 / 152.
Reason for change
Inclusion of all current models

Complaint
High-frequency ticking or pulsing noise from high-pressure pump and/or fuel injectors.


Cause
For high-pressure pump:

Pump lifting piston inlet in piston seat.

For fuel injectors:

Closing noise of injector tips following injection.

This noise described in both instances is the normal sound level of components, characteristic to the high-pressure injection system.


Remedy
In the event of any noise complaints a reference vehicle must be used for comparison to assess the actual noise level.

Compare the noise in similar condition with or without foam enclosure for the high-pressure pump, with the engine hood closed, outside and from the inside the cabin.

Refer to general procedures and documentation related to engine complaints.