Mercedes-Benz Om651 2.1L Diesel Engine Oil Change Diy

How to Change the Oil on a Mercedes-Benz OM651 2.1L Diesel

ByRushit Hila, PE, ASE Certified Updated onOct 18, 2026

Reviewed/Verified by:

Rushit Hila

PE, ASE Certified

Rushit Hila is the founder of YOUCANIC and a passionate advocate for empowering car owners through knowledge. With a background in automotive diagnostics and years of hands-on repair experience, Rushit leads the YOUCANIC team in creating practical, easy-to-follow guides and tools that help drivers fix their own vehicles. His mission is simple: make car repair less intimidating and more accessible for everyone.

Is it time to change the engine oil in your Mercedes-Benz OM651 2.1L Diesel Engine? Learn how to replace your Mercedes-Benz engine oil and filter by following the steps below. The video and pictures are from a 2014 GLK250 BlueTec, but the procedure applies to other Mercedes-Benz models equipped with the OM651 engine.

At a Glance

Engine: Mercedes-Benz OM651 2.1L diesel (shown on a 2014 GLK250 BlueTEC)
Oil: 5W-30 meeting MB 229.51 or 229.52
Capacity: About 6.9 US qt (6.5 L) with filter
Torque: Drain plug 30 Nm (22 ft-lb), filter cap 25 Nm (18 ft-lb)
Time: About 1 hour
Finish: Check the dipstick and reset the service reminder

Are you more of a visual learner? Follow along with our video guide below!

What you will need

There are a couple of tools and parts you will need to replace the engine oil in your Mercedes-Benz OM651 engine:

Parts

Engine Oil SAE 5W-30 (low ash, diesel approved)
- Capacity: About 6.9 US qt (6.5 L) with filter. Fill to about 6.5 qt, then check the dipstick
- Specification: MB 229.51 or MB 229.52 (required for BlueTEC engines with a diesel particulate filter)
Engine Oil Filter
- See the part numbers below.

Tools

Oil Filter Wrench or Pliers
Oil drain pan
Funnel
Work Gloves
Ramps or Floor Jack
Jack stands (x2)
Ratchet
Metric Sockets
Wheel Chocks
Torque Wrench

Procedure

1. Jack up the vehicle. Drive the vehicle up onto ramps, or use a floor jack, and place the transmission in Park. Next, turn the ignition off and remove the key.

2. Secure the vehicle with jack stands. The jack stands must be used to support the vehicle frame. Do not place a jack stand under the engine or suspension components. Place the jacks under the designated jack points around the vehicle. If you’re not sure where they are, look up the location online, or find it in your Mercedes-Benz’s user manual.

3. Place wheel chocks behind the rear tires to prevent the vehicle from rolling; alternatively, use a block or large brick if wheel chocks are unavailable. Ensure parking brakes are engaged.
If the engine has been running for a long time, allow it to cool down for at least 15 minutes. If the engine is already cool, you can continue to the next step.

4. Remove the splash shield from under the engine. To remove the splash shield, you need a ratchet and socket to remove the eight 8 mm bolts around it. In some models, you have a combination of screws and plastic retainers. Please remove all of them to drop the cover and access the oil drain bolt.

5. Slide a drain pan and place it under the drain plug. Make sure the drain pan is large enough to catch all of the engine oil.

NOTE: Slightly offset the drain pan because, when the drain plug is removed, oil will shoot out rather than down.

Use a 13mm wrench to remove the drain plug. Loosen the drain bolt by turning it counterclockwise. If removing the drain bolt is extremely difficult, check that you are not turning it in the wrong direction.

4. Drain engine oil.

⚠️CAUTION: If the engine is still hot, the engine oil will also be hot, which can cause burns if it comes into contact with your skin.

Carefully remove the drain plug and let the engine oil drain for several minutes.

5. Replace the copper washer. Replacing the copper washer every time you change the engine oil is recommended. Do not reinstall the drain plug without a new copper washer.

6. Install Drain Plug. Initially, screw it by hand to avoid cross-threading. Use a torque wrench to tighten the drain plug to specification; do not use a breaker bar. See the recommended torque at the end of this guide.

7. Locate the engine oil filter and replace it. Use an oil wrench to remove the filter cartridge and keep a drain pan nearby. Oil may drip when you remove the filter cartridge. Remove the old filter cartridge, then put the new one in. Replace the o-rings on the filter cartridge as well.

8. Put the engine filter back in place and use an oil wrench to seal it properly: torque to 25 Nm.

9. Open the engine oil cap and add engine oil. Clean the area around the cap with a damp paper towel or microfiber cloth to prevent dirt and debris from entering the reservoir.

Remove Engine Oil Cap

Use a funnel to pour the engine oil and prevent spills.

Add Oil Via The Engine Oil Filler Hole

10. Check engine oil level. If you had the engine running or just added oil to the engine, you should wait at least five minutes to take the subsequent measurement. This will allow the engine oil to return to the pan so that you can take an accurate measurement. If the level is low, add one quart at a time, wait a few minutes, and recheck the levels.

11. Reset the oil service reminder on the instrument cluster. If the cluster menu will not reset it, a scan tool such as the YOUCANIC UCAN-II Pro can reset the service reminder on supported models.
12. Inspect the engine for oil leaks from the drain plug and filter.

Torque Specifications

Oil filter: 25 Nm (18 ft-lb)
Oil drain plug: 30 Nm (22 ft-lb)

Applicable Oil Filters

Frequently Asked Questions

What oil does the Mercedes OM651 diesel need?

BlueTEC OM651 engines with a diesel particulate filter need low ash oil approved to MB 229.51 or MB 229.52, typically 5W-30.

How much oil does an OM651 take?

About 6.9 US quarts (6.5 L) with a filter change. Add a little less, run the engine, then top up using the dipstick.

What is the OM651 drain plug torque?

Tighten the drain plug to 30 Nm (22 ft-lb) with a new sealing washer. The oil filter cap is tightened to 25 Nm.

Which oil filters fit the OM651?

Compatible filters include Fram CH11277, Beck/Arnley 041-0867 and the other part numbers listed in this guide.

Check these troubleshooting and repair guides for more help on your Mercedes-Benz.

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