Mercedes-Benz C-Class 220 CDI Engine Replacement Compare Prices & Get Quotes

A replacement engine for a C220 CDI typically costs between £550 and £4,800 depending on the engine code and condition. Used OM646 units start from £550-£1,400, reconditioned from £1,200-£2,800, and fully rebuilt OM651 engines from £2,500-£4,800. Labour for supply & fit adds £500-£1,000.

• Used OM646.963 (W203 C220 CDI): £550-£1,300
• Rebuilt OM646.811 (W204 C220 CDI): £2,000-£3,500
• Rebuilt OM651.911 (W204 C220 CDI): £2,500-£4,800

"Black Death" refers to injector seal failure that affects OM611, OM612 and OM646 engines. The copper washer seal between the injector and cylinder head degrades, allowing combustion gases to escape. This creates hard, black carbon deposits around the injector. Symptoms include a ticking or chuffing noise, a strong diesel smell in the cabin, hissing sounds from the engine, and visible black tar-like residue. If left untreated, the injector can seize in the cylinder head, requiring expensive extraction and head repairs.

• Affects OM646 engines in W203 and W204 C220 CDI
• Early repair (£180-£300 per injector) prevents injector seizure
• Ignoring it can lead to £1,200+ head repair costs

It depends on the engine. The OM646 (W203 and early W204) uses a duplex timing chain at the front of the engine, which is robust and does not require scheduled replacement. The OM651 (W204 C220 CDI from 2008) uses a timing chain at the rear of the engine, which is prone to stretching. A metallic rattling noise on cold start is the classic warning sign.

• OM646: front-mounted duplex timing chain - durable, no scheduled replacement
• OM651: rear-mounted timing chain - prone to stretch at 80k-120k miles
• Rattling on cold start is the warning sign for OM651

It depends on the generation and condition. A W203 C220 CDI is typically worth £1,500-£3,000 - a full engine replacement often exceeds the car's value, making a used engine or targeted repair (injector seals, turbo) more economical. A W204 C220 CDI is worth £3,500-£8,000 - a rebuilt OM646 or OM651 engine (£2,000-£4,800) can be a worthwhile investment if the car is in good condition. Always compare the cost of repair against the car's market value.

• W203 (2000-2007): used engine or targeted repair
• W204 (2007-2014): rebuilt engine with warranty is viable for good condition cars
• Vehicle worth over £4,000: replacement usually justifies the cost

The OM646 is a 2.2-litre diesel used in the W203 facelift and early W204 C220 CDI (2003-2009) with a front-mounted duplex timing chain. The OM651 is a 2.1-litre diesel introduced in the W204 C220 CDI from 2008, featuring a rear-mounted timing chain and 2,000 bar rail pressure. Both produce 170 hp in W204 form, but the OM646 is considered more robust due to its simpler design.

• OM646: 2.2L, 143-170 hp, front timing chain, W203/W204 (2003-2009)
• OM651: 2.1L, 170 hp, rear timing chain, W204 (2008-2014)

Power loss in the C220 CDI is most commonly caused by turbocharger issues, particularly sticking variable vanes from carbon buildup. Other causes include EGR valve clogging, injector seal failure ("Black Death"), and on OM651 engines, timing chain stretch causing cam timing drift. A diagnostic check with Mercedes STAR or compatible equipment is essential to identify the exact cause.

• Turbocharger vanes - sticking from carbon buildup
• EGR valve - clogging from carbon deposits
• Injector seals - "Black Death" causing compression loss
• Timing chain stretch (OM651) - power loss + rattling