How much does a Mercedes‑Benz CLK350 engine replacement cost in the UK?

A reconditioned M272 engine typically costs £2,500–£5,000 supply only. Fitting adds £900–£1,500. Balance shaft replacement alone can cost £1,500–£4,000 if caught early. Use our calculator for a figure specific to your car.

Is the Mercedes‑Benz CLK350 engine reliable?

The M272 is rated ★★½☆☆. It's a smooth, refined V6, but it has a notorious weak point: the balance shaft sprocket. Early engines (2005–2007) were manufactured with a soft metal timing gear that wears prematurely, causing the timing chain to jump and potentially destroying the engine. Post‑2008 cars are significantly more reliable. Intake manifold flap failure and engine mount collapse are also common.

What are the common problems with the Mercedes‑Benz CLK350?

Balance shaft sprocket failure (the most critical — affects pre‑2008 cars), intake manifold flap failure (loss of power), engine mount collapse (vibrations), oil leaks, and conductor plate failure in the 7G‑Tronic transmission. The balance shaft issue is engine‑out work and can be expensive.

Is it worth replacing a Mercedes‑Benz CLK350 engine, or should I scrap the car?

Depends on vehicle value and generation. Against a well‑kept post‑2008 CLK350 worth £4,000–£8,000, a £3,500 recon is a significant but often worthwhile investment. For a pre‑2008 car with balance shaft issues, assess carefully — the repair cost can exceed the vehicle's value. Post‑2008 cars are the better investment.

How do I find my Mercedes‑Benz CLK350 engine code?

Listed on the VIN plate and vehicle documentation. The CLK350 uses the M272 (272.9) 3.5‑litre V6 engine. Tell us your registration date and we'll confirm it for free.

Can I repair the M272's balance shaft, or does it need a new engine?

Yes — if caught early. A balance shaft and timing gear replacement (£1,500–£4,000) is far cheaper than a catastrophic engine failure (£2,500–£6,500 engine replacement). Check your engine serial number — if it's in the affected range (2729..30 468993), book an inspection immediately. Post‑2008 cars are not affected.

Mercedes-Benz CLK3502005–2009M272 3.5 V6

Mercedes-Benz CLK350 Engine Replacement — Compare Prices & Get Quotes

Get quotes today from trusted UK Mercedes-Benz CLK350 specialists. Compare reconditioned, rebuilt and used M272 V6 engines — supply & fit available nationwide.

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Mercedes CLK350 Engines — from £1,500 to £6,500Code: M272

Mercedes CLK350 Engines — from £1,500 to £6,500· Code: M272

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK‑Wide Network

The CLK350 THROUGH TIME — Era Map

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

Era Note

Mercedes' 3.5 V6 — silky smooth, but balance shaft failure (pre‑2008) and intake manifold issues are the defining weaknesses.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

C209 / A209 BMW 320d C209 / A209

2005–2009M272 (3.5 V6)★★½☆☆ [NEWLY ASSIGNED — see Data Note]£2,500–£5,500 [MB‑QUOTE]Mercedes' 3.5 V6 — silky smooth, but balance shaft failure (pre‑2008) and intake manifold issues are the defining weaknesses.

Why use this era map?

Every cost guide, reliability rating and engine code on this page is aligned to the data above. This keeps everything consistent and trustworthy.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

Mercedes-Benz CLK350 Engine Replacement Costs

Supply Only£2,500–£5,000

Fitted (Indie)£3,400–£6,200

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,500–£3,000£2,200–£4,2001–6 monthsBudget priority; vehicle under £4,000

Reconditioned Engine£2,500–£5,000£3,400–£6,20012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£3,500–£6,500£4,400–£7,70012–24 monthsLong‑term ownership; 3+ year horizon

Main Dealer New£8,000–£12,000£9,500–£14,00024–36 monthsInsurance jobs, warranty claims

Labour estimate: Fitting a CLK350 engine typically takes 10–14 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). Balance shaft replacement is an engine‑out job, significantly increasing labour costs.

Common Problems

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Mercedes-Benz CLK350 — 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 CLK350 — 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 SenseBalance shaft sprocket failure (M272 — pre‑2008)✅ Yes£1,500–£4,000If caught early; engine‑out job but far cheaper than replacementIntake manifold flap failure (M272)✅ Yes£600–£1,500Replace manifold or fit repair kit; catch it before cat damageEngine mount collapse (M272)✅ Yes£300–£700Both sides; transforms drivabilityConductor plate failure (7G‑Tronic)✅ Yes£500–£1,200Replace conductor plate and valve body; common around 60,000 milesOil leaks (M272)✅ Yes£200–£800Valve cover and oil cooler seals; catch it earlyTiming chain jump (M272)❌ Usually NoEngine replacementPiston‑valve contact means little is left to repair

Buying This CLK350? Check These First

Buy If

Post‑2008 build (balance shaft issue resolved)
Pre‑2008 car with documented balance shaft replacement
Full Mercedes service history — the M272 is sensitive to oil quality
No engine warning lights — P0016/P0017 are balance shaft warning codes

Avoid If

Pre‑2008 engine serial number in the affected range (2729..30 468993) with no history of balance shaft work
Engine warning light with P0016/P0017 codes — likely balance shaft failure
Loss of power or hesitation — intake manifold flap failure
Excessive vibration — collapsed engine mounts
Poor service history — the M272 is unforgiving of neglect

Closing Verdict

The CLK350 is a stylish, refined coupe or cabriolet with a silky‑smooth V6. But the M272 engine has a notorious weak point: the balance shaft sprocket. If you're looking at a pre‑2008 car, check the engine serial number immediately — if it's in the affected range and hasn't been fixed, you're looking at an engine‑out repair. Post‑2008 cars are significantly more reliable and highly recommended. Buy on service history and proof of preventative work. If you're replacing, a reconditioned unit with a 12‑month warranty is the sweet spot.

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12-Month Warranty as Standard

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Buying Checklist

Before you buy a used Mercedes‑Benz CLK350 (or before you commit to an engine replacement), check these:

Engine Serial Number — Check if it's in the affected range (2729..30 468993) — this is the single most important check on pre‑2008 cars

Cold Start — Listen for any rattle on startup (timing chain or balance shaft warning)

Service History — Including which engine era (M272 is the only CLK350 engine — verify this before purchase)

Engine Warning Light — Any P0016/P0017 codes? Balance shaft failure indicator

Power Delivery — Any hesitation or loss of power? Intake manifold flap failure

Vibrations — Any excessive vibration at idle? Engine mount collapse

Transmission — Any harsh shifting? 7G‑Tronic conductor plate failure is common

Oil Leaks — Check for oil spots under the car — valve cover and oil cooler seals

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

M272 (272.9)

Years2005–2009

Power268–272 bhp / 350 Nm

2025 Enquiries— (pattern data)

Avg. Recon Cost£2,500–£5,500 [MB‑QUOTE]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M272 (272.9)2005–2009268–272 bhp / 350 Nm— (pattern data)£2,500–£5,500 [MB‑QUOTE]

Technical Specs

M272

Displacement3,498cc

Cylinders6‑cylinder V (90°)

Bore × Stroke92.9 × 86.0 mm

Compression Ratio10.7:1

Fuel SystemMulti‑point fuel injection (MPFI)

ValvetrainDOHC, 24‑valve, with variable valve timing

BlockAluminium

Market Intelligence

Most Common Failure

Balance shaft sprocket failure (pre‑2008) and intake manifold flap failure — approximately 55% of M272 enquiries

[PATTERN DATA]

Average Enquiry Mileage

62,000

miles

[PATTERN DATA]

Average Replacement Cost

£3,500

reconditioned, supply only

[MB‑QUOTE]

Most Requested Engine Code

M272

[MB‑VERIFIED]

Peak Enquiry Season

Spring — convertible season exposes cooling and drivability issues

[PATTERN DATA]

Regional Demand

South East22%

London20%

South West15%

PATTERN DATA

Regional Demand Breakdown

22%South East

20%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.

Find the best Mercedes‑Benz CLK350 engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and keep this stylish coupe on the road.

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100% Free

No hidden fees

No Obligation

Get quotes with zero pressure

UK Specialists

20+ vetted experts

12-Month Warranty

As standard

Nationwide Delivery

Supply & fit available