Mercedes W213 OM651 Heat Exchanger Engine Oil Cooler Diesel 2.2 A6511800865

Mercedes W213 OM651 Heat Exchanger Engine Oil Cooler is an original component from the Oil coolers and lines group, designed for OM651 diesel units paired with an automatic transmission. This used oil cooler allows for a technically correct and cost-effective repair of the lubrication system in your Mercedes, while maintaining factory standards for flow and heat dissipation.

Specifications and technical data

• SKU: A6511800865
• Mark: Mercedes (Genuine OE)
• Condition: Used
• OEM Part Number: A6511800865
• Substitutable numbers: A6511800865, A 651 180 08 65
• Fuel type: Diesel
• Gearbox type: Automatic
• Category: Oil Coolers & Lines

Purpose and function in the lubrication system

The oil cooler in the OM651 diesel engine is responsible for stabilizing the operating oil temperature, which directly impacts the durability of the powertrain and the performance of the automatic transmission if the system is integrated. For the 2.2 Diesel version, maintaining proper oil cooling is particularly important due to the high thermal loads typical of modern diesel engines.

The original Mercedes oil cooler ensures:

• a heat exchange surface properly matched to the characteristics of the OM651 engine,
• stable oil operating conditions across a wide range of loads,
• consistency with the factory architecture of the lubrication and cooling system.

Benefits of using an original oil cooler

Using a factory component in the oil cooling system translates into predictable operating parameters for the entire powertrain. The original design tailored to the OM651 engine minimizes the risk of leaks, improper coolant flow, or incompatibility with engine block mounts.

Key advantages include:

• preservation of factory mounting points and connections for oil and cooling lines,
• compatibility with the operating parameters of the 2.2 Diesel unit in the Mercedes W213,
• suitability as a replacement within the designated interchangeable part numbers for the same product family.

Application in Mercedes vehicles with automatic transmission

In vehicles with an automatic transmission, stable engine oil temperature is important not only for the engine itself but also for its interaction with the gearbox. The oil cooler adapted for the Diesel + automatic configuration helps maintain consistent operating conditions during city driving, highway driving, and under higher loads, reducing the risk of overheating and oil viscosity drop.

In practice, this translates into:

• more predictable lubrication of moving engine components,
• reduced risk of premature wear of bearings and the turbocharger,
• better stability of operating parameters over long service cycles.

Condition, selection, and installation aspects

The offered oil cooler is a used part, which allows for a significant reduction in repair costs while maintaining the manufacturer's original specifications. Before installation, a standard workshop procedure is recommended, including checking the system for leaks, ensuring the cleanliness of the lines, and verifying proper integration with the existing cooling and lubrication system.

To ensure correct selection, it is worth verifying the part's compatibility with the specific engine and transmission configuration of your vehicle. Dedicated manufacturer markings and classification under the Oil coolers and lines category are helpful, as they facilitate finding the right components within the same functional group.

Technical support and additional materials

For users interested in learning more about the impact of the cooling system on powertrain durability, we have prepared a guide. Read the article Engine cooling system – overheating, repair, and used radiators to better understand the relationship between the oil cooler and engine lifespan in modern designs.

If you are planning a comprehensive repair or upgrade of the engine area in your Mercedes and need other components from the same group, such as additional coolers, oil lines, or connection elements, check the available parts in the Mercedes oil coolers and lines category.