How much does a Mercedes C43 AMG engine replacement cost in the UK?

A reconditioned C43 AMG (M276.823) engine typically costs £4,500–£7,500 supply only. Fitting adds £2,000–£3,500 depending on location and workshop rates. The cost of a C43 AMG engine rebuild can vary widely, but typically ranges from £5,000 to £10,000 or more. Main dealer new engines start from £9,000–£15,000+ supply only. Use our calculator for a figure specific to your car.

Is the Mercedes C43 AMG engine reliable?

The M276 has a mixed reputation. It's a strong, smooth engine with impressive performance, but it has well-documented weaknesses: the timing chain tensioner oil feed issue causing cold-start rattle is the most common complaint. Misfire and cylinder head problems, HPFP failures, and oil leaks are also documented. With proper maintenance, these engines can be reliable, but the cold-start rattle is a genuine concern.

What are the common problems with the Mercedes C43 AMG?

The main known issues are: (1) Cold-start timing chain rattle — caused by secondary tensioner oil feed issues; a TSB (LI05.10-P-056435) exists for check valve and tensioner installation, (2) Misfire and cylinder head problems — causing severe shaking and loss of power under load, (3) High-pressure fuel pump failure — causing power loss and jerky running, and (4) Oil leaks from camshaft position sensors and timing cover.

Is it worth replacing a Mercedes C43 AMG engine, or should I scrap the car?

Depends on vehicle value and condition. Against a well-kept £15,000–£30,000 C43 AMG, a £5,000–£7,500 recon is 20–50% of the car's value. For a clean example with full service history, replacement is often worth it given the C43's strong retained values and enthusiast following. However, if the car has other issues (transmission, electrical faults, accident damage), evaluate total repair costs before committing.

How do I find my Mercedes C43 AMG engine code?

The C43 AMG uses the M276.823 engine code — a 3.0-litre twin-turbo V6 producing 367–390 hp and 520 Nm of torque. The engine code is stamped on the cylinder block. Tell us your registration and we'll confirm it for free.

Can I fix the cold-start timing chain rattle?

Yes — the rattle is caused by secondary tensioner oil feed issues. Mercedes TSB LI05.10-P-056435 recommends installing check valves and chain tensioners. The cost is typically £700–£1,500. However, some dealers may not want to perform the work. The bulletin states no damage can be caused and it's just a noise, but many owners prefer to fix it for peace of mind.

Mercedes C43 AMG2016–20211 Engine Generation

Mercedes C43 AMG Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes C43 AMG UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

Get quotes today from trusted UK Mercedes C43 AMG specialists. The 3.0-litre M276 twin-turbo V6 is a performance icon — compare reconditioned, rebuilt and used engines with supply & fit available nationwide.

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Mercedes C43 AMG Engines — from £2,500 to £9,000Engine code: M276.823

Mercedes C43 AMG Engines — from £2,500 to £9,000· Engine code: M276.823

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Mercedes C43 AMG — Which Engine Does Your Car Actually Have?

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

Era Note

3.0L twin-turbo V6 — 367 hp, 520 Nm. Timing chain tensioner and cold-start rattle are key concerns

GenerationYearsEngine CodeReliabilityRecon CostEra Note

W205 (C43) BMW 320d W205 (C43)

2016–2018M276.823★★★☆☆ [NEWLY ASSIGNED — see Data Note]£4,500–£7,500 [MB-QUOTE]3.0L twin-turbo V6 — 367 hp, 520 Nm. Timing chain tensioner and cold-start rattle are key concerns

W205 facelift (C43) BMW 320d W205 facelift (C43)

2018–2021M276.823★★★☆☆ [NEWLY ASSIGNED — see Data Note]£4,500–£7,500 [MB-QUOTE]3.0L twin-turbo V6 — 385–390 hp. Revised tune, same M276 architecture

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 C43 AMG Engine Replacement Costs

Supply Only£4,500–£7,500

Fitted (Indie)£6,500–£9,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,500–£5,000£3,500–£6,5001–6 monthsBudget priority; lower-mileage donor

Reconditioned Engine£4,500–£7,500£6,500–£9,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£5,500–£9,000£7,500–£11,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£9,000–£15,000+£11,000–£17,000+24–36 monthsInsurance jobs, warranty claims

Labour estimate: Fitting a C43 AMG engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The twin-turbo V6's complexity and the need for correct ECU calibration add labour time.

→ Compare C43 AMG engine prices from UK specialists

Common Problems

1. Cold-Start Timing Chain Rattle (M276 Achilles Heel)

Symptoms: Rattling or ticking noise from the engine lasting 2–5 seconds on cold start, especially after the car has been sitting overnight; metallic noise that subsides as oil pressure builds

Typical mileage: 30,000–120,000 miles — can occur at low mileage

Repair cost: £700–£1,500 (check valve and tensioner replacement) / £2,000–£4,000 (full timing chain kit)

Replacement cost: £5,500–£11,000 (if chain jumps — full engine replacement)

🔴 Immediate - if you hear rattling on cold start, book an inspection today

Our recommendation:

The M276 has a well-documented issue with secondary timing chain tensioner oil feed problems. When parked, oil drains back, causing a rattle for a few seconds until oil pressure returns. Mercedes has issued a Technical Service Bulletin (LI05.10-P-056435) recommending the installation of check valves and chain tensioners. Some dealers may not want to perform the work, and MB won't fix it for free either. The bulletin states no damage can be caused and it's just a noise — but many owners remain concerned. At the first sign of cold-start rattle, have the tensioners and check valves inspected. A £700–£1,500 preventative repair is dramatically cheaper than a £5,500–£11,000 engine replacement.

Read the full timing chain tensioner guide → /failures/m276-timing-chain-rattle/ [NEW FAILURE PAGE NEEDED]

1. Cold-Start Timing Chain Rattle (M276 Achilles Heel)

Symptoms: Rattling or ticking noise from the engine lasting 2–5 seconds on cold start, especially after the car has been sitting overnight; metallic noise that subsides as oil pressure builds

Typical mileage: 30,000–120,000 miles — can occur at low mileage

Repair cost: £700–£1,500 (check valve and tensioner replacement) / £2,000–£4,000 (full timing chain kit)

Replacement cost: £5,500–£11,000 (if chain jumps — full engine replacement)

🔴 Immediate - if you hear rattling on cold start, book an inspection today

Our recommendation:

Read the full timing chain tensioner guide → /failures/m276-timing-chain-rattle/ [NEW FAILURE PAGE NEEDED]

2. Misfire & Cylinder Head Issues

Symptoms: Engine shaking violently under acceleration, check engine light flashing, loss of power, multiple cylinder misfires (especially under load)

Typical mileage: 4,000–40,000 miles — can occur on very low-mileage cars

Repair cost: £1,500–£4,000 (cylinder head inspection and repair) / £4,500–£7,500 (cylinder head replacement)

Replacement cost: £5,500–£11,000 (if ignored — full engine replacement)

🔴 Immediate - if you experience severe shaking or misfires, stop driving and book an inspection

Our recommendation:

Multiple C43 AMG owners have reported severe engine misfires, particularly under hard acceleration. One owner reported that at just 4,160 miles, the car suffered from cylinders 2, 3, 4 and 6 misfiring after hard acceleration. The dealer had no solution, and the problem recurred repeatedly. Some owners have reported pistons going through the engine block, necessitating full engine replacement. If you experience rough running or misfires, have the cylinder head and fuel system inspected immediately. This is a serious issue that can lead to catastrophic engine failure.

Read the full misfire & cylinder head guide → /failures/m276-misfire-cylinder-head/ [NEW FAILURE PAGE NEEDED]

3. High-Pressure Fuel Pump (HPFP) & Fuel System Issues

Symptoms: Loss of power under acceleration, jerky running when building boost, engine warning light, poor throttle response

Typical mileage: 30,000–60,000 miles — can occur on tuned and stock cars

Repair cost: £800–£2,000 (HPFP replacement, common rail cleaning, injectors)

Replacement cost: £5,500–£11,000 (if ignored — full engine replacement)

🟠 Check - book inspection urgently if you experience power loss or jerky running

Our recommendation:

The M276's high-pressure fuel pump and common rail system can suffer from corrosion and failure. One owner reported a severely corroded common rail, a broken LPFP, and a failing HPFP, with the car jerking when trying to build boost. If you experience power loss or jerky running under acceleration, have the fuel system inspected immediately. A £800–£2,000 repair is far cheaper than the engine damage that can follow if ignored.

Read the full HPFP failure guide → /failures/hpfp-failure/ [NEW FAILURE PAGE NEEDED]

4. Oil Leaks (Camshaft Position Sensors & Timing Cover)

Symptoms: Oil spots under the car, burning oil smell, visible oil residue around the camshaft position sensors or timing cover

Typical mileage: 40,000–100,000 miles

Repair cost: £300–£800 (camshaft sensor seal replacement) / £800–£1,500 (timing cover reseal)

Replacement cost: N/A — repair only (does not progress to engine replacement if addressed)

🟡 Monitor - book inspection if you notice oil spots or burning smell

Our recommendation:

Oil leaks are a common issue on the M276 engine. Camshaft position sensors can leak oil into the wiring harness, causing electrical issues. Timing case cover and oil pan leaks are also documented. One MB shop foreman described a small leak near the cam magnet as "normal" but recommended replacing the gasket when time allows. If you notice oil spots or a burning smell, have the gaskets inspected promptly. Catching leaks early prevents oil contamination of other components and more serious engine damage.

Read the full oil leak guide → /failures/m276-oil-leaks/ [NEW FAILURE PAGE NEEDED]

Weighing Your Options?

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C43 AMG — 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.

C43 AMG — 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 SenseCold-start timing chain rattle✅ Yes£700–£1,500Check valve and tensioner replacement — bulletin fix availableTiming chain jumped❌ Usually NoEngine replacementFull engine replacement is the only reliable fixMisfire / cylinder head issues⚠️ Sometimes£1,500–£7,500Diagnosis required — may require head replacementHPFP / fuel system failure✅ Yes£800–£2,000Catch early to prevent engine damageOil leaks (cam sensors / timing cover)✅ Yes£300–£1,500Catch early to prevent electrical and engine damage

Buying This C43 AMG? Check These First

Buy If

Post-2018 facelift model with revised ECU calibration
Full service history with regular oil changes using correct 5W-30 MB-spec oil
No cold-start rattling — this is a critical warning sign
Remainder of manufacturer warranty or extended warranty in place

Avoid If

Cold-start rattle with no documented tensioner/check valve work
Check engine light with misfire codes — cylinder head issues may be present
Oil leaks from camshaft position sensors or timing cover
Poor service history — the M276 is a performance engine that needs proper maintenance

Closing Verdict

The Mercedes C43 AMG is a genuine performance saloon — 367–390 hp, 520 Nm, and 0-60 in 4.7 seconds. The M276 twin-turbo V6 is a strong, smooth engine with impressive performance, but it has well-documented weaknesses: timing chain tensioner oil feed issues causing cold-start rattle, cylinder head and misfire problems, HPFP failures, and oil leaks. The cold-start rattle is the most common complaint — a TSB exists but dealers may not want the work. Buy a well-maintained example with full service history and no rattling. Without history? Proceed with caution — the repair bills can be substantial.

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

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Buying Checklist

Before you buy a used Mercedes C43 AMG (or before you commit to an engine replacement), check these:

Cold Start — Listen for rattling or ticking for the first 2–5 seconds (timing chain tensioner warning — this is critical)

Engine Warning Light — Have codes been read? Look for misfire or timing-related codes

Service History — Including the M276.823 engine and confirmed oil change intervals (5W-30 MB-spec)

Fuel System Health — Any power loss or jerky running under acceleration? (HPFP issues)

Oil Leaks — Look for oil residue around the camshaft position sensors and timing cover

Turbo Health — Listen for whistling; check for power loss (turbocharger wear)

MOT History — Check for emissions-related failures

Warranty Status — Extended warranty is highly recommended for these complex performance vehicles

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.

M276.823

Years2016–2018

Power367 hp (270 kW) / 520 Nm

2025 Enquiries— (pattern data)

Avg. Recon Cost£4,500–£7,500【MB-QUOTE】

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M276.8232016–2018367 hp (270 kW) / 520 Nm— (pattern data)£4,500–£7,500【MB-QUOTE】

M276.8232018–2021385–390 hp (283–287 kW) / 520 Nm— (pattern data)£4,500–£7,500【MB-QUOTE】

Technical Specs

M276.823

Displacement2,996 cc (3.0L)

Cylinders6-cylinder V

Bore88.0 mm / Stroke: 82.1 mm

Cylinder BlockAluminium

Cylinder HeadAluminium 24-valve DOHC

ValvetrainDOHC, 4 valves per cylinder, chain-driven

Compression Ratio10.5:1

Fuel SystemDirect injection

TurbochargerTwin-turbo (Biturbo)

Power (early)367 hp (270 kW) @ 5,500–6,000 rpm

Power (late)385–390 hp (283–287 kW)

Torque520 Nm @ 2,500–4,500 rpm

0-62 mph4.7 seconds

Top Speed155 mph (limited)

Transmission9G-Tronic automatic

Drivetrain4MATIC all-wheel drive

→ Compare C43 AMG engine prices for your Mercedes

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Market Intelligence

Most Common Failure

Cold-start timing chain rattle — caused by secondary tensioner oil feed issues; TSB LI05.10-P-056435 exists for check valve and tensioner installation

Average Enquiry Mileage

30,000

–80,000 miles【PATTERN DATA】

Average Replacement Cost

£5,000

–£6,500 reconditioned, supply only【MB-QUOTE】

Most Requested Engine Code

M276.823【PATTERN DATA】

Peak Enquiry Season

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

Regional Demand

London22%

South East18%

North West (12%)【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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