Description

This is a fully reconditioned Garrett GT20V turbocharger for the Mercedes E320 CDI fitted with the 3.0L OM642 V6 diesel engine. As a genuine Garrett unit, reconditioned by Gap Turbos, it offers original equipment performance and reliability for your vehicle.

This turbocharger is a variable nozzle turbine (VNT) type, which uses adjustable internal vanes to control exhaust gas flow, providing excellent response across the engine’s rev range. It is controlled by a sophisticated electronic actuator, which is included and calibrated as part of this assembly. Common failure modes for this specific unit are directly related to the OM642 engine’s characteristics. The most frequent issue we encounter is the seizure of the VNT mechanism due to excessive carbon and soot build-up, often exacerbated by short journeys or issues with the EGR system. This leads to the vanes sticking in one position, causing either overboost or underboost fault codes and putting the vehicle into ‘limp mode’. Another prevalent problem is the failure of the electronic actuator itself, which can report position sensor faults or cease to function entirely. Standard bearing wear from contaminated or degraded engine oil can also lead to failure of the central housing rotating assembly (CHRA), resulting in noise, smoke, and oil consumption.

At our Birmingham workshop, we recondition these units to the highest standard. The turbo is completely disassembled, and all components are deep-cleaned and inspected. The CHRA is rebuilt with new bearings and seals before being balanced on our VSR machine to tighter tolerances than the original factory specification. The VNT mechanism is meticulously cleaned and re-calibrated for correct operation. We offer this part as a direct exchange for your old unit. Alternatively, Gap Turbos can provide a complete supply and fit service, which includes full diagnostics, an engine oil and filter change, and replacement of the critical oil feed pipe.

What this turbocharger fits

This reconditioned turbocharger is a direct replacement for the Garrett 765155-5007s, also known by the Mercedes part number A6420901480. It is designed for the following vehicle configuration:

• Make: Mercedes-Benz
• Model: E320 CDI (W211 / S211 chassis)
• Engine: OM642 (3.0L V6 Diesel)
• Power Output: 224 HP
• Years: 2005 – 2011

While primarily listed for the E-Class, this turbocharger also fits other Mercedes models that use the same OM642 engine variant, such as the ML-Class, S-Class, and R-Class. Please verify the part number on your original unit to ensure compatibility.

All our reconditioned turbochargers are supplied with a comprehensive 24-month warranty. Please contact us with your vehicle registration to confirm fitment and receive a precise quote.

Specifications

Vehicle fitment

• Mercedes E320 CDI V6

Common faults & troubleshooting

• Vehicle enters ‘limp mode’ with reduced power: This is the classic symptom of the VNT mechanism sticking, causing the ECU to detect an overboost or underboost condition and restrict engine performance to protect it.
• A high-pitched whistle or siren noise on acceleration: This usually points to a boost leak in the pipework between the turbo and the engine, or less commonly, damaged compressor wheel fins.
• Visible blue smoke from the exhaust, especially on start-up: This indicates that the turbo’s internal oil seals have failed, allowing engine oil to pass into the exhaust system where it is burned.
• Engine Management Light (EML) is illuminated: Specific fault codes like ‘Boost Pressure Deviation’ or ‘Actuator Position Sensor Circuit’ point directly towards a fault with the turbocharger or its electronic control unit.
• Excessive engine oil consumption with no visible leaks: If the engine is otherwise healthy, failing seals within the turbo’s central cartridge (CHRA) are a likely cause, as oil is lost into the intake or exhaust.

Fitting notes for this unit

• Mandatory Oil Feed Pipe Replacement: The oil feed pipe for the OM642 engine is a critical component that can become restricted over time. Failure to replace the oil feed pipe and banjo bolts will invalidate the warranty and likely cause premature failure of the new unit.
• Prime the Turbo Before Starting: Use the supplied syringe to inject 10-20ml of fresh engine oil into the turbo’s oil feed port. While injecting, slowly spin the compressor wheel by hand for 30 seconds to ensure the bearings are fully lubricated before the first start.
• Inspect Exhaust Manifolds: The V6 OM642 manifolds are known to delaminate internally, which can break off and destroy the turbine wheel of the new turbocharger. Always inspect the manifolds for integrity before fitting.
• Crank Engine with Fuel Disabled: Before the first start, disable the fuel system (e.g., by pulling the fuel pump fuse) and crank the engine for 15 seconds. This allows oil pressure to build up throughout the system and reach the turbocharger, preventing a dry start.
• Check for Leaks and Bed-In: Once started, allow the engine to idle for 5-10 minutes. During this time, carefully check all oil and air connections for leaks. Do not apply high engine load or rev the engine until this initial idling period is complete.

Alternative part numbers

This turbo is also referenced by:

• A6420901480 — Mercedes Turbocharger OEM A6420901480 (Mercedes E320 CDI V6, OM642, 224hp)

Frequently asked questions