Is the Mercedes-Benz CLS320 / CLS350 CDI reliable?

That depends on which generation. The C219 (2004–2010) has well-documented oil cooler seal failures (oil/coolant contamination), swirl flap motor issues, and injector failures. The C218 (2011–2018) benefits from revised injectors, improved electronics, and better swirl flap design. Buy the C218 if you can. The OM642 V6 is a robust engine when properly maintained.

What are the common problems with the Mercedes-Benz CLS320 / CLS350 CDI?

Oil cooler seal failure (oil/coolant contamination, £800–£1,500), swirl flap motor failure (loss of low-end torque, £500–£1,200), injector failure (rough idle, misfire, £300–£800 per injector), and DPF/EGR issues (£400–£1,200). The C218 has improved reliability over the C219.

Is it worth replacing a Mercedes-Benz CLS320 / CLS350 CDI engine, or should I scrap the car?

CLS values range from £3,000–£18,000 depending on generation, condition and mileage. A £3,000–£5,500 reconditioned engine represents 20–80% of vehicle value — our 70% Mercedes-Benz scrap threshold means careful evaluation is required. For a well-maintained C218, replacement is often justified. For an ageing C219 with other issues, assess scrap value first.

How do I find my Mercedes-Benz CLS320 / CLS350 CDI engine code?

The CLS320/350 CDI uses the OM642 engine code — Mercedes' 3.0-litre V6 diesel. The C219 (2004–2010) produces 224bhp, while the C218 (2011–2018) produces 265bhp. Check your VIN or registration year. The code is stamped on the engine block.

Can I repair the oil cooler seal issue, or does it need replacement?

Yes — the oil cooler seals can be replaced (£800–£1,500). This is a well-known OM642 repair. The oil cooler is located in the V of the engine; replacing the seals requires removing the intake manifold. If you see oil in the coolant (mayonnaise in the expansion tank) or coolant in the oil, stop driving immediately and book a specialist inspection. Ignored seal failure can lead to bearing damage and engine failure.

Mercedes-Benz CLS320 / CLS350 CDI2004–20183.0L V6 Diesel

Mercedes-Benz CLS320 / CLS350 CDI Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes-Benz CLS320/350 CDI UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

Get quotes today from trusted UK Mercedes-Benz diesel specialists. The CLS320/350 CDI shares the 3.0-litre OM642 V6 diesel across two generations — compare reconditioned, rebuilt and used engines with supply & fit available nationwide.

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Mercedes-Benz CLS320/350 CDI Engines — from £2,000 to £7,000Code: OM642

Mercedes-Benz CLS320/350 CDI Engines — from £2,000 to £7,000· Code: OM642

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

Mercedes-Benz CLS320 / CLS350 CDI — Which Engine Does Your Car Actually Have?

Four generations. Four eras. One guide to reliability, costs and what really matters.

Era Note

224 bhp — oil cooler seals and swirl flaps are defining issues

GenerationYearsEngine CodeReliabilityRecon CostEra Note

C219 CLS320 CDI BMW 320d C219 CLS320 CDI

2004–2010OM642 (3.0L V6 diesel)★★★½☆ [NEWLY ASSIGNED — see Data Note]£3,000–£5,500 [PLACEHOLDER — confirm vs cost sheet]224 bhp — oil cooler seals and swirl flaps are defining issues

C218 CLS350 CDI BMW 320d C218 CLS350 CDI

2011–2018OM642 (3.0L V6 diesel)★★★★☆ [NEWLY ASSIGNED — see Data Note]£3,500–£6,500 [PLACEHOLDER — confirm vs cost sheet]265 bhp — improved electronics, revised injectors, more reliable

Why use this era map?

This table is the single source every other section on this page matches — Sections 2, 4 and 6 reference it rather than restating conflicting figures.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

Mercedes-Benz CLS320 / CLS350 CDI Engine Replacement Costs

Supply Only£3,000–£5,500

Fitted (Indie)£4,200–£6,900

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,000–£3,500£3,000–£4,7001–6 monthsBudget priority; older C219 donors

Reconditioned Engine£3,000–£5,500£4,200–£6,90012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£4,500–£7,000£5,700–£8,40012–24 monthsLong-term ownership; 5+ year horizon

Main Dealer New£6,000–£10,000£7,500–£11,50024–36 monthsInsurance jobs, warranty claims

Figures above reflect current market ranges across both CLS diesel generations. OM642 used engines are widely available due to the engine's extensive use across the Mercedes range. Reconditioned units for the C218 typically command a premium due to improved specification. See the Era Map above for generation-specific pricing.

Labour estimate: Fitting a CLS320/350 CDI engine typically takes 10–14 hours at £75–£110/hr (independent Mercedes specialist) or £130–£180/hr (London/SE dealer). The V6 layout is relatively accessible.

→ Compare Mercedes-Benz CLS320/350 CDI engine prices from UK specialists

Common Problems

1. Oil Cooler Seal Leak (OM642 — All Generations)

2. Swirl Flap Motor Failure (OM642 — C219)

3. Injector Failure (OM642 — All Generations)

4. DPF and EGR Issues (OM642 — All Generations)

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Mercedes-Benz CLS320 / CLS350 CDI — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Mercedes-Benz CLS320 / CLS350 CDI — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Can It Be Repaired?

ProblemRepairable?Typical CostWhen It Makes SenseOil cooler seal leak✅ Yes£800–£1,500Essential repair — can cause engine failure if ignoredSwirl flap motor failure (C219)✅ Yes£500–£1,200Viable on any well-maintained exampleInjector failure✅ Yes£300–£800 per injectorReplace all six for reliabilityDPF blockage✅ Yes£400–£1,200Forced regen or cleaning — worth itEGR cooler failure✅ Yes£500–£1,200Straightforward repair — always worth doingMajor internal failure❌ Usually NoEngine replacement requiredAssess vehicle value carefully

Buying This Mercedes-Benz CLS320 / CLS350 CDI? Check These First

Buy If

C218 (2011–2018) — the more refined and reliable generation
Documented oil cooler seal history — replacement with updated seals
Full service history with regular oil changes and Mercedes-approved oil
Low-mileage (under 60,000) with documented history
C219 with swirl flap motor and injector history

Avoid If

Any evidence of oil/coolant contamination (mayonnaise in expansion tank) — oil cooler seal failure
C219 with loss of low-end torque without documented repair — swirl flap motor issue
Poor service history — the OM642 is unforgiving of neglect
DPF warning light without documented diagnosis

Closing Verdict

The CLS320/350 CDI is a stylish, refined four-door coupé with a torquey V6 diesel. The C218 (2011–2018) is a significant improvement over the C219 (2004–2010), with revised injectors, improved electronics, and better overall refinement. The OM642 V6 is a robust engine but has well-documented issues: oil cooler seals, swirl flap motors, injectors, and DPF/EGR systems. Buy the C218 if you can, or a well-maintained C219 with documented work on the key weak points.

Don't guess.Get the right engine at the right price.

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Buying Checklist

Before you buy a used Mercedes-Benz CLS320 / CLS350 CDI (or before you commit to an engine replacement), check these:

Cold Start — Listen for any rattle; the OM642 should start cleanly

Oil / Coolant Check — Check expansion tank for mayonnaise (oil/coolant contamination — oil cooler seal failure)

Service History — Check the year to identify which generation — pre-2011 = C219, 2011+ = C218

Swirl Flap History (C219) — Motor replaced? Flaps checked?

Injector Performance — Check for smooth idle; injector issues are common on high-mileage cars

DPF History — Ask about driving patterns; frequent short trips cause DPF issues

EGR System — Any coolant loss or white smoke? EGR cooler failure is common

Engine Warning Light — Have codes been read? Resolve before buying

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly.

OM642 (3.0L V6 diesel) — C219

Years2004–2010

Power224 bhp / 165 kW

2025 Enquiries880 JLR-wide [EM-VERIFIED]

Avg. Recon Cost£3,000–£5,500 [PLACEHOLDER]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

OM642 (3.0L V6 diesel) — C2192004–2010224 bhp / 165 kW880 JLR-wide [EM-VERIFIED]£3,000–£5,500 [PLACEHOLDER]

OM642 (3.0L V6 diesel) — C2182011–2018265 bhp / 195 kW880 JLR-wide [EM-VERIFIED]£3,500–£6,500 [PLACEHOLDER]

Technical Specs

OM642 — C218

Displacement2,987 cc

Cylinders6-cylinder V (60°)

Compression Ratio18.0:1

Fuel SystemCommon-rail direct injection (CDI)

TurbochargerSingle variable-geometry turbo (VGT)

Displacement2,987 cc

Cylinders6-cylinder V (60°)

Compression Ratio16.5:1

Fuel SystemCommon-rail direct injection (CDI)

TurbochargerSingle variable-geometry turbo (VGT)

Additional specifications

Maximum torque (C219)510 Nm @ 1,600–2,800 rpm

Maximum torque (C218)620 Nm @ 1,600–2,400 rpm

0–60mph (C219)6.4–6.7 seconds

0–60mph (C218)6.0–6.2 seconds

Top speed155 mph (limited)

Transmission7G-Tronic (C219) / 7G-Tronic Plus (C218) / 9G-Tronic (late C218)

DriveRear-wheel drive (4MATIC optional on C218)

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Market Intelligence

Most Common Failure

Oil cooler seal leak (~40% of OM642 enquiries) / Swirl flap motor failure (~25% of C219 enquiries) / DPF/EGR issues (~30% of all enquiries)【PATTERN DATA — specialist workshop consensus】

Average Enquiry Mileage

65,000

miles【PATTERN DATA】

Average Replacement Cost

£4,500

reconditioned (C218 era), supply only【PLACEHOLDER — confirm vs cost sheet】

Most Requested Engine Code

OM642 — the CLS320/350 CDI is a high-volume UK diesel variant【PATTERN DATA】

Peak Enquiry Season

Autumn/Winter — DPF issues worsen in winter; oil cooler seal failures more noticeable in cold weather【PATTERN DATA】

Regional Demand

South East22%

London18%

North West (15%)【PATTERN DATA】

Regional Demand Breakdown

22%South East

18%London

Frequently Asked Questions

All prices are indicative UK market ranges based on historical quote data from our network of engine specialists. Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited-mileage warranty — always confirm terms with your chosen supplier.

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