3.0L V6 Engine Complete Assembly for 2015-2016 Mercedes-Benz

A quick look at your own vehicle makes sure the right engine shows up:

• Confirm that the 6th and 7th digits of your VIN are 6H.
• Verify your drivetrain is AWD (4MATIC) or RWD.
• Locate the engine code stamped on your original engine block to confirm it reads 276.820 (or 276820).

What the install really takes — plan and budget with confidence:

Special tools this job needs:

• Mercedes Camshaft Alignment/Holding Tool Kit (OEM equivalent: 278589002300)
• Engine hoist and heavy-duty subframe support/jack/lift table
• Mercedes-compatible diagnostic scanner (XENTRY/DAS)

Budget for these consumables at install:

• Premium synthetic engine oil meeting Mercedes-Benz specification MB 229.5 (approx. 7.4 quarts / 7.0 liters)
• New OEM-quality oil filter (e.g., Mann-Filter HU 7025 z)
• Mercedes-approved G48 (blue) or G40 (pink/violet) coolant (MB 325.0 specification)
• 6 new OEM spark plugs (NGK or Bosch, indexed and torqued precisely to 23 Nm)
• Intake manifold gaskets (plenum gaskets)
• Valve cover gaskets (if covers are removed)
• Front upper timing cover sealant (Loctite 5900 or Mercedes OEM sealant)
• Turbocharger oil feed/return line O-rings and gaskets
• Exhaust manifold gaskets and turbo-to-manifold gaskets
• New torque-to-yield (TTY) bolts for critical components (cylinder heads, timing components, or engine mounts)
• New aluminum oil pan drain plug washer

What your vehicle’s computers will need after the swap:

What’s involved: SCN (Software Calibration Number) coding and Crankshaft Position Sensor Relearn

sources differ: Arm 1 states no programming is required if reusing the original ECU, while Arm 2 states SCN coding is mandatory for swapping the engine itself. The more cautious value 'model_dependent' is selected. If replacing the ECU, full SCN coding via an online Mercedes-Benz XENTRY diagnostic system is required to marry the electronics to the immobilizer.

Pro tips for a smooth first start-up — hand them to whoever does the install:

• AWD (4MATIC) Front Axle Pass-Through: The front left intermediate axle shaft passes directly through a tube cast into the engine's upper oil pan. You must carefully slide the intermediate shaft out of the oil pan bearing and inspect/replace the bearing (A2229800015) if rough.
• Spark Plug Indexing: Spark plugs must be torqued precisely to 23 Nm (17 ft-lbs) so the electrode faces the injector to prevent severe misfires.
• Turbo Transfer & Priming: Since this engine is sold LESS TURBO, you must transfer your existing turbochargers and prime them with oil before starting the engine.
• Check Valve Retrofit: Inspect and install timing chain check valves (TSB LI05.10-P-056435) on an engine stand before installing the engine.
• Dropping the Drivetrain: The most efficient way to remove the engine is to drop the entire front subframe with the engine and transmission attached as a single unit.
• Fragile Plastic Components: Be extremely careful with plastic coolant pipes, vacuum lines, and sensor connectors which become brittle with age.

Easy to get right once you know them:

• Reusing Oil-Saturated Camshaft Sensors: Reusing old leaking sensors will contaminate the replacement engine's wiring harness and ruin the ECU. Always install brand-new camshaft sensors and solenoids, and install sacrificial pigtail harnesses (A271150015605).
• Assuming All 3.0L M276 Engines are Identical: Trying to buy an M276 engine from a C43 AMG or GLE400 to put into a CLS400. AMG variants have different compression ratios, larger turbos, different oil pans, and different accessory layouts.
• Failing to Swap the Oil Pan (AWD vs RWD): The AWD oil pan has the axle shaft tube running through it, which will not clear the subframe of a RWD car.
• Not Replacing the Front Upper Timing Cover Sealant: Reusing old sealant or using cheap RTV will result in immediate oil leaks.
• Reusing Torque-to-Yield (TTY) Bolts: Reusing stretch bolts for components like cylinder heads or the crankshaft pulley will lead to failure.
• Attempting Install Without XENTRY: Underestimating the need for dealer-level SCN programming, resulting in a no-start condition.

Not issues with the units on this page — the manufacturer documented these for every engine of this family, wherever you buy one. Handy for your installer: