Your diagram will show small "Teflon" rings and plastic arms. These break. You don't need a $1,200 new manifold; you can buy a repair kit (L shaped levers) for $30 if you know which part to search for.
If you own a Mercedes-Benz from the mid-2000s to early 2010s—think the W203 C-Class, W211 E-Class, or R171 SLK—chances are you are running the M272 V6 engine . This 24-valve, 60-degree V6 was the workhorse of the lineup, displacing between 2.5L and 3.5L. Mercedes Benz M272 Engine Parts Diagram
While the M272 is known for its smooth power delivery, it is also famous for a few critical failure points (looking at you, balance shaft sprocket). Whether you are troubleshooting a rough idle, rebuilding a top end, or just trying to understand where that oil leak is coming from, Your diagram will show small "Teflon" rings and plastic arms
If your diagram shows the intermediate shaft gear (part #272 030 03 01), take note. If the engine serial number is lower than #2729..30 088933, that gear is likely soft and failing. The fix requires removing the transmission, oil pan, and timing cover—a $3,000+ job. If you own a Mercedes-Benz from the mid-2000s
Disclaimer: Always verify part numbers for your specific VIN. Mercedes changed designs constantly mid-production.