How much does a Mercedes C300 Petrol engine replacement cost in the UK?

A reconditioned C300 petrol engine costs £3,000–£6,000 supply only depending on which generation you have. Used engines are available from £1,200–£3,500. Mercedes C-Class engine replacements typically cost £3,500 or more. Fitting adds £1,000–£1,600 depending on your location and workshop. Main dealer new engines can exceed £10,000.

Is the Mercedes C300 Petrol engine reliable?

It depends on which generation you have. The M276 V6 (W204 facelift, 2011–2014) is widely considered the most reliable C300 petrol. The M272 V6 (W204 pre-facelift, 2008–2011) has intake manifold flap and balance shaft issues. The M274 turbo four-cylinder (W205, 2015–2021) has well-documented timing chain, cracked piston, and wrist pin issues. The M264 is improved but has camshaft adjuster and cooling system concerns.

What are the common problems with the Mercedes C300 Petrol?

The most frequently reported issues vary by engine. M272: Intake manifold flap failure and balance shaft wear. M276: Timing chain tensioner wear and oil leaks. M274: Timing chain problems, cracked pistons, wrist pin issues, and PCV system failures. M264: Camshaft adjuster issues and cooling system faults.

Is it worth replacing a Mercedes C300 Petrol engine, or should I scrap the car?

Depends on vehicle value and which generation. Against a well-kept £18,000 W205 C300, a £4,000 recon is 22% — worth it. Against a tired £5,000 W204 example, the same recon approaches our 70% Mercedes threshold — get a scrap valuation first. The M276 W204 facelift is the most desirable for reliability.

How do I find my Mercedes C300 Petrol engine code?

Listed on the VIN plate and vehicle documentation. W204 pre-facelift (2008–2011): M272.947. W204 facelift (2011–2014): M276.957. W205 (2015–2021): M274 (early) or M264 (late). The chassis code and year are the easiest tells.

Can I repair the timing chain on the C300, or does it need full engine replacement?

Yes — if caught early. A preventative timing chain and tensioner replacement costs £800–£2,500. If ignored and the chain snaps, the engine is an interference design — pistons and valves collide, resulting in catastrophic engine damage. At the first sign of cold-start rattle, book an inspection immediately. Regular oil changes using MB 229.5 spec oil are the single most effective preventative measure. For the M274, also check for wrist pin/piston issues if you experience engine failure.

Mercedes C300 Petrol2008–present3 Engine Generations

Mercedes C300 Petrol Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes C300 Petrol UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

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Mercedes C300 Petrol Engines — from £1,200 to £8,500Common codes: M272, M276, M274, M264

Mercedes C300 Petrol Engines — from £1,200 to £8,500· Common codes: M272, M276, M274, M264

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The C300 PETROL THROUGH TIME — Era Map

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

Era Note

The original C300 — a naturally aspirated V6. Balance shaft wear and intake manifold flaps are the main concerns.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

W204 (pre-facelift) BMW 320d W204 (pre-facelift)

2008–2011M272.947 (3.0L V6)★★★☆☆ [NEWLY ASSIGNED — see Data Note]£3,000–£5,500 [PLACEHOLDER — confirm vs cost sheet]The original C300 — a naturally aspirated V6. Balance shaft wear and intake manifold flaps are the main concerns.

W204 (facelift) BMW 320d W204 (facelift)

2011–2014M276.957 (3.5L V6)★★★★☆ [NEWLY ASSIGNED — see Data Note]£3,500–£6,000 [PLACEHOLDER]The improved V6 — more power, better economy. Timing chain tensioners and oil leaks are the known patterns.

W205

2015–2021M274 (2.0L Turbo I4) / M264 (2.0L Turbo I4)★★★☆☆ [NEWLY ASSIGNED — see Data Note]£2,500–£5,500 [PLACEHOLDER]The turbo four-cylinder era. M274 is prone to timing chain and piston issues; M264 is more reliable but has camshaft adjuster and cooling system concerns.

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 C300 Petrol Engine Replacement Costs

Supply Only£3,000–£6,000

Fitted (Indie)£4,200–£7,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,200–£3,500£2,200–£5,0001–6 monthsBudget priority; vehicle under £4,000

Reconditioned Engine£3,000–£6,000£4,200–£7,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£5,000–£8,500£6,200–£10,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£7,000–£12,000+£8,500–£14,000+24–36 monthsInsurance jobs, warranty claims

Figures above reflect the C300 petrol engine family. Mercedes C-Class engine replacements typically cost £3,500 or more. Used M272 engines are available from approximately £1,200. Main dealer new engines can exceed £10,000.

Labour estimate: Fitting a C300 petrol engine typically takes 12–16 hours at £70–£100/hr (independent) or £120–£180/hr (London/SE dealer). V6 engines (M272/M276) require more labour than four-cylinder engines (M274/M264).

→ Compare C300 petrol engine prices from UK specialists

Common Problems

1. Timing Chain & Tensioner Wear (All Engines)

Symptoms: Rattling noise on cold start (2–3 seconds), metallic ticking from the engine, engine warning light, grinding noise on startup, eventual catastrophic failure if ignored.

Typical mileage: 60,000–100,000 miles; M274 chain lifespan approximately 80,000 miles (±20,000); M272 balance shaft issues can appear earlier.

Repair cost: £800–£2,500 (chain + tensioner replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£8,500 (if chain snaps and valves strike pistons)

🔴 Immediate - if you hear rattle, book an inspection today

Our recommendation:

Timing chain problems are the single most significant concern across the C300 engine family. The M272 has balance shaft wear issues on early models. The M276's timing chain tensioners are known weak points. The M274 is prone to timing chain problems. At the first sign of cold-start rattle, get the chain and tensioners inspected immediately. Regular oil changes using MB 229.5 spec oil are essential.

Read the full timing chain failure guide

1. Timing Chain & Tensioner Wear (All Engines)

Symptoms: Rattling noise on cold start (2–3 seconds), metallic ticking from the engine, engine warning light, grinding noise on startup, eventual catastrophic failure if ignored.

Typical mileage: 60,000–100,000 miles; M274 chain lifespan approximately 80,000 miles (±20,000); M272 balance shaft issues can appear earlier.

Repair cost: £800–£2,500 (chain + tensioner replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£8,500 (if chain snaps and valves strike pistons)

🔴 Immediate - if you hear rattle, book an inspection today

Our recommendation:

Read the full timing chain failure guide

2. M274 — Cracked Pistons & Wrist Pin Failure

Symptoms: Engine failure, loss of power, misfire, engine warning light, metallic knocking from the engine, complete engine seizure.

Typical mileage: 13,000–80,000 miles (can occur at low mileage)

Repair cost: £2,000–£4,000 (piston replacement / engine rebuild)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£8,500 (if engine is beyond repair)

🔴 Immediate - if you hear knocking, stop driving immediately

Our recommendation:

The M274 engine has a well-documented issue with cracked pistons (particularly cylinder 1) and wrist pin failures. A US petition was filed attributing M274 engine failure to "wrong sized wrist-pins". Mercedes issued a service bulletin for wrist pin / piston problems on a specific engine number range. If you experience engine failure or knocking, do not drive the car — catastrophic failure is imminent.

Read the full piston failure guide

3. Intake Manifold Flap Failure — M272 V6 (W204 pre-facelift)

Symptoms: Loss of power, rough idle, engine warning light, reduced fuel economy, rattling noise from the intake manifold.

Typical mileage: 60,000–100,000 miles

Repair cost: £500–£1,200 (intake manifold repair kit or replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £3,000–£8,500 (if debris damages the engine)

🟠 Check - book inspection urgently

Our recommendation:

The M272 V6's intake manifold flaps are made of plastic and can break over time. When the plastic lever arm breaks, the internal flaps either get stuck open or stuck closed. This can cause performance issues and, in severe cases, debris can enter the engine. A repair kit is available. This issue affects the W204 pre-facelift C300 (2008–2011).

Read the full intake manifold failure guide

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C300 Petrol — 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.

C300 Petrol — 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 SenseTiming chain wear (all engines)✅ Yes£800–£2,500Preventative — catches the fault before catastrophic failureBalance shaft wear (M272 early)✅ Yes£1,500–£3,500Specialist repair; catch it earlyIntake manifold flap failure (M272)✅ Yes£500–£1,200Repair kit available; cheaper than engine replacementCracked piston / wrist pin (M274)⚠️ Sometimes£2,000–£4,000If caught early, pistons can be replaced; often requires full engine rebuildPCV system failure (M274)✅ Yes£500–£1,500Well-understood repair; prevent long-term engine damageTiming chain snap (valve contact)❌ Usually No£3,000–£8,500Typically requires full engine replacement or complete rebuild

Buying This C300 Petrol? Check These First

Buy If

Post-2011 M276 V6 (facelift W204) — the most reliable C300 petrol
M274: Engine outside the affected wrist pin number range; documented timing chain service
M264: Post-2018 build with cooling system service records
Full Mercedes service history with evidence of regular oil changes using MB 229.5 spec oil

Avoid If

M272: Cold-start rattle or intake manifold noise with no documented repair
M274: Engine failure or knocking with no diagnosis; check engine number range for wrist pin issues
M264: Cooling system faults or camshaft adjuster noise
Any engine: Poor service history — these engines are unforgiving of neglect

Closing Verdict

The C300 Petrol badge spans three distinct eras of Mercedes engine philosophy — the smooth naturally aspirated V6 of the W204, the improved M276 V6 of the facelift, and the turbocharged four-cylinder era of the W205. The M276 is widely considered the most reliable of the three, while the M274 has well-documented timing chain, piston, and wrist pin issues. The M264 is improved but still has camshaft adjuster and cooling system concerns. Buy on documented history, not on faith. A well-maintained C300 is a £15,000–£30,000 premium saloon; a neglected one is a £5,000 engine replacement waiting to happen.

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

→ Compare C300 petrol engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes C300 Petrol (or before you commit to an engine replacement), check these:

Cold Start — Listen for rattling, ticking, or grinding (timing chain or tensioner warning)

Service History — including which engine era (M272/M276/M274/M264) and confirmed oil-change intervals using MB 229.5 spec oil

Timing Chain Check — Any history of timing chain or tensioner replacement? (essential for all engines)

Wrist Pin Check (M274) — Check engine number against the affected range for wrist pin/piston issues

Intake Manifold Check (M272) — Any loss of power, rough idle, or rattling? (intake flap warning)

Coolant Check (M264) — Any history of coolant loss or cooling system faults?

Engine Warning Light — Have codes been read? Any unresolved timing, piston, or cooling system issues?

MOT History — Check for emissions-related failures

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.

M272.947 (3.0L V6)

Years2008–2011

Power228–231 hp (170 kW) @ 6,000 rpm · 300 Nm @ 2,500–5,000 rpm

2025 Enquiries— (pattern data)

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

Engine CodeGenerationYearsPower2025 EnquiriesAvg. Recon Cost

M272.947 (3.0L V6)2008–2011228–231 hp (170 kW) @ 6,000 rpm · 300 Nm @ 2,500–5,000 rpm— (pattern data)£3,000–£5,500 [PLACEHOLDER]

M276.957 (3.5L V6)2011–2014248–252 hp (185 kW) @ 6,500 rpm · 340 Nm @ 3,500–4,500 rpm— (pattern data)£3,500–£6,000 [PLACEHOLDER]

M274 (2.0L Turbo I4) / M264 (2.0L Turbo I4)2015–2021241–245 hp (180 kW) @ 5,500 rpm · 370 Nm @ 1,300–4,000 rpm— (pattern data)£2,500–£5,500 [PLACEHOLDER]

Technical Specs

M272.947Displacement: 2,996 cc · Cylinders: V6 · Compression Ratio: 11.3:1 · Fuel: Multi-point injection · Aspiration: Naturally aspirated

M276.957Displacement: 3,498 cc · Cylinders: V6 · Compression Ratio: 12.0:1 · Fuel: Direct injection · Aspiration: Naturally aspirated

M274 / M264Displacement: 1,991 cc · Cylinders: 4-cylinder inline · Compression Ratio: 9.8:1 · Fuel: Direct injection · Turbocharger: Single turbo

→ Compare C300 petrol engine prices for your Mercedes

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Market Intelligence

Most Common Failure (M272)

Intake manifold flap failure and balance shaft wear (early models)

Most Common Failure (M276)

Timing chain tensioner wear and oil leaks

Most Common Failure (M274)

Timing chain wear, cracked pistons / wrist pin issues, PCV system failures

Most Common Failure (M264)

Camshaft adjuster issues, cooling system faults

Average Enquiry Mileage

50,000

–80,000 miles

[PATTERN DATA]

Average Replacement Cost

£3,000

–£6,000 reconditioned, supply only

[PLACEHOLDER — confirm vs cost sheet]

Most Requested Engine Code

M276 / M274

[PATTERN DATA]

Peak Enquiry Season

Winter — cold starts expose timing chain issues【PATTERN DATA】

Regional Demand

London22%

South East18%

Midlands14%

PATTERN DATA

Regional Demand Breakdown

22%London

18%South East

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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