Autopapyrus · Mercedes-Benz C-Class W203 2.0 CDI 122 hp (2006)
https://autopapyrus.com/guides/mercedes-benz/c-class/engine-oil-and-oil-filter-change/

Compiled automatically from service literature and owner experience. Specs are for the typical configuration — check them against your exact car before you start.

Mercedes-Benz C-Class W203 2.0 CDI 122 hp (2006): Engine Oil and Oil Filter Change

The Mercedes diesel of this generation (OM646 series, listed in catalogs as CDI) has its oil changed together with the cartridge filter, which sits in a housing on top of the engine. The usual change interval is 10,000-15,000 km or once a year. If you mostly make short trips or drive in heavy traffic, stay closer to 10,000 km. Drain the oil with the engine warm.

Difficulty: Easy Time: 40-60 minutes Steps: 12

Parts

№	Part	Alternatives
01	5W-30 engine oil, MB 229.51 (or MB 228.51)about 6-7 L (6.3-7.4 qt)
02	Oil filter element, cartridge type, with two seals included	Mann, Mahle, Bosch
03	Drain plug washernew

Tools

Wrench or socket for the drain plug (hex or TORX, depending on the plug, check yours)
32 mm socket for the oil filter housing cap
torque wrench
drain pan (8-10 L / 8.5-10.5 qt)
funnel
rags
jack with jack stands or an inspection pit
oil filter wrench if needed

There's a full repair manual for this car Every system, wiring diagrams and torque specs — not just this job. Haynes and 12 more. See manuals →

Step by step

12 steps

Warm the engine up to operating temperature (5-10 minutes of driving), then shut it off. Park the car on level ground and apply the parking brake.
Open the hood and remove the decorative plastic engine cover. Find the round oil filter housing cap on top of the engine, and unscrew the oil filler cap so the oil drains faster.
Raise the car with a lift or jack stands, or drive it over a pit. Remove the lower engine undertray if one is installed.
Place the pan under the oil pan, remove the drain plug and let the oil drain completely (about 10-15 minutes). Be careful: the oil is hot.
While the oil drains, unscrew the filter housing cap with the 32 mm socket (counterclockwise), placing rags under the housing. Pull out the cap together with the filter element and let the remaining oil drain off.
Remove the old element from the cap and replace the seals: the large one on the cap and the small one on the center tube. If they were not included in the kit, buy them separately. Lubricate the new seals with clean oil. Wipe dirt and oil residue from the seat in the housing.
Install the new filter element in the cap and screw the cap into the housing. Tighten to about 25 N·m (18 lb-ft) (20-25 N·m / 15-18 lb-ft is acceptable; do not overtighten the plastic housing).
Wipe the drain hole, install a new washer and tighten the drain plug. Tightening torque is about 25-30 N·m (18-22 lb-ft) (check against the marking on the plug and the oil pan; overtightening can strip the threads in an aluminum oil pan).
Pour about 6 L (6.3 qt) of oil in through the filler neck, wait 2-3 minutes, and check the level with the dipstick. Top up to the MAX mark, but not above it. Close the filler cap.
Start the engine for 1-2 minutes. The oil pressure warning light should go out within 1-2 seconds. Check for leaks around the filter and drain plug.
Shut off the engine, wait 5 minutes, check the dipstick level again and top up if needed. Install the undertray and the decorative cover.
Reset the service interval counter (ASSYST) through the instrument cluster menu, if equipped, and take the used oil to a recycling collection point.

Common mistakes and warnings

Use only oil with MB 229.51 or 228.51 approval
Do not use ordinary oils without MB approval: they quickly clog the particulate filter and accelerate wear
Check the exact fill capacity with the filter against the engine marking and the dipstick; the figure in this article is approximate
Overfilling is just as harmful as underfilling: the oil foams and can get into the intake, which can cause the diesel to run away