How much does a Mercedes‑AMG GT / GT S / GT C engine replacement cost in the UK?

A reconditioned M178 engine typically costs £5,000–£10,000 supply only depending on variant, with the GT C sitting at £7,000–£15,000. Fitting adds £1,100–£1,800. Main dealer new engines can exceed £25,000. Use our calculator for a figure specific to your car.

Is the Mercedes‑AMG GT / GT S / GT C engine reliable?

The M178 is rated ★★★½☆ — it's considered a robust and remarkably durable engine. Owners have logged tens of thousands of miles with tuned engines producing over 700 bhp without significant issues. However, known issues include wastegate actuator/boost problems, stuck injectors, dynamic engine mount failures, and transmission oil leaks.

What are the common problems with the Mercedes‑AMG GT / GT S / GT C?

Wastegate actuator/boost issues, dynamic engine and transmission mount failures (particularly GT C/GT S), stuck injectors, faulty exhaust flaps, and transmission oil leaks. The engine is generally robust with proper maintenance — 200,000–300,000 km examples are not uncommon.

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

Depends on vehicle value. Against a well‑kept AMG GT worth £25,000–£60,000, a £7,500 recon is a manageable 12–30% of the vehicle's value — worth it for a well‑maintained example. Given the AMG GT's status and strong retained values, replacement is usually viable for vehicles in good condition.

How do I find my Mercedes‑AMG GT engine code?

Listed on the VIN plate and vehicle documentation. The AMG GT / GT S / GT C uses the M178 4.0‑litre twin‑turbo V8. Tell us your registration date and we'll confirm it for free.

Can I repair the M178's wastegate actuator, or does it need a new engine?

Yes — the wastegate actuator and boost control issues are repairable, typically costing £500–£1,500. If caught early, it does not require engine replacement. At the first sign of power loss or whistling, book an inspection immediately.

Mercedes-AMG GT / GT S / GT C2015–2022M178 4.0 V8 Biturbo

Mercedes-AMG GT / GT S / GT C Engine Replacement — Compare Prices & Get Quotes

Get quotes today from trusted UK Mercedes‑AMG GT specialists. Compare reconditioned, rebuilt and used M178 engines for the C190/R190 — supply & fit available nationwide.

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Mercedes‑AMG GT V8 Engines — from £4,000 to £15,000Code: M178

Mercedes‑AMG GT V8 Engines — from £4,000 to £15,000· Code: M178

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK‑Wide Network

The AMG GT / GT S / GT C THROUGH TIME — Era Map

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

Era Note

Entry‑level M178 — robust and tunable; wastegate and cooling system are the main watchpoints.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

C190/R190 (GT) BMW 320d C190/R190 (GT)

2015–2020M178 (456–469 bhp)★★★½☆ [NEWLY ASSIGNED — see Data Note]£5,000–£9,000 [MB‑QUOTE]Entry‑level M178 — robust and tunable; wastegate and cooling system are the main watchpoints.

C190/R190 (GT S) BMW 320d C190/R190 (GT S)

2015–2020M178 (503–522 bhp)★★★½☆ [NEWLY ASSIGNED — see Data Note]£6,000–£11,000 [MB‑QUOTE]Mid‑range M178 — the sweet spot; dynamic engine mounts can fail.

C190/R190 (GT C) BMW 320d C190/R190 (GT C)

2017–2022M178 (550 bhp)★★★½☆ [NEWLY ASSIGNED — see Data Note]£7,000–£15,000 [MB‑QUOTE]Top‑spec M178 — 550 bhp, rear‑wheel steering; stuck injectors and transmission leaks are the main watchpoints.

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‑AMG GT / GT S / GT C Engine Replacement Costs

Supply Only£5,000–£10,000

Fitted (Indie)£6,100–£11,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£4,000–£7,000£5,000–£8,3003–6 monthsBudget priority; vehicle under £20,000

Reconditioned Engine£5,000–£10,000£6,100–£11,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£7,000–£15,000£8,200–£16,50012–24 monthsLong‑term ownership; 3+ year horizon

Main Dealer New£18,000–£25,000£20,000–£28,00024–36 monthsInsurance jobs, warranty claims; dealer costs can exceed £25,000

Labour estimate: Fitting an AMG GT engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The M178's hot‑vee layout requires significant disassembly.

Common Problems

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Mercedes‑AMG GT / GT S / GT C — 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‑AMG GT / GT S / GT C — 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 SenseWastegate actuator / boost issues (M178)✅ Yes£500–£1,500Specialist repair; catch it before turbo damageDynamic engine/transmission mounts (M178)✅ Yes£800–£2,000Replace with updated parts; common on GT C/GT SStuck injectors (M178)✅ Yes£400–£1,200Replace failed injectors; catch it before cat damageExhaust flap failure (M178)✅ Yes£300–£800Replace exhaust flap actuators; common issueTransmission oil leak (M178)✅ Yes£500–£1,500Some model years have recalls; check before buyingTiming chain stretch (M178)✅ Yes£2,000–£5,000Rare but possible; regular oil changes prevent

Buying This AMG GT / GT S / GT C? Check These First

Buy If

Full Mercedes service history with documented oil changes (every 5,000–7,000 miles)
Evidence of dynamic mount replacement on GT C/GT S
Post‑2017 build (many early recalls resolved)
Good service history — the M178 is robust but demands care

Avoid If

Loss of power or boost issues with no diagnosis
Vibration or clunking — potential dynamic mount failure
Rough idle or misfire codes — injector issues
Transmission oil leaks — some model years have recalls
Poor service history — the AMG GT is unforgiving of neglect

Closing Verdict

The Mercedes‑AMG GT is a masterpiece — a hand‑built V8 sports car that delivers phenomenal performance. The M178 engine is robust and remarkably tunable, with owners reporting over 700 bhp on stock internals without issues. However, it has known weaknesses: wastegate actuators, dynamic engine mounts, stuck injectors, and transmission leaks. Buy on service history and proof of preventative maintenance. 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‑AMG GT / GT S / GT C (or before you commit to an engine replacement), check these:

Cold Start — Listen for any rattle on startup (timing chain issues are rare but possible)

Service History — Including which engine variant (GT, GT S, or GT C) — see the Era Map above

Boost Health — Test acceleration; any loss of power or whistling? Wastegate actuator risk

Vibrations — Any vibration through the cabin? Dynamic engine/transmission mount failure indicator

Idle Quality — Any rough idle or misfire? Stuck injector risk

Exhaust Flaps — Do the exhaust flaps work correctly? Faulty actuators are common

Transmission Leaks — Any oil leaks from the transmission case? Some model years have recalls

Engine Warning Light — Have codes been read? Any unresolved boost, injector, or mount issues?

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

M178 (GT)

Years2015–2020

Power456–476 bhp / 600–630 Nm

2025 Enquiries— (pattern data)

Avg. Recon Cost£5,000–£9,000 [MB‑QUOTE]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M178 (GT)2015–2020456–476 bhp / 600–630 Nm— (pattern data)£5,000–£9,000 [MB‑QUOTE]

M178 (GT S)2015–2020503–522 bhp / 650–670 Nm— (pattern data)£6,000–£11,000 [MB‑QUOTE]

M178 (GT C)2017–2022550 bhp / 680 Nm— (pattern data)£7,000–£15,000 [MB‑QUOTE]

Technical Specs

M178

Displacement3,982cc

Cylinders8‑cylinder V (90°)

Bore × Stroke83 mm × 92 mm

Compression Ratio10.5:1

Fuel SystemDirect injection

TurbochargerTwin‑turbo, BorgWarner, hot‑vee layout

ValvetrainDOHC, 4 valves per cylinder

Market Intelligence

Most Common Failure

Wastegate actuator / boost issues and dynamic engine mounts — approximately 50% of M178 enquiries

[PATTERN DATA]

Average Enquiry Mileage

35,000

miles

[PATTERN DATA]

Average Replacement Cost

£7,500

reconditioned, supply only

[MB‑QUOTE]

Most Requested Engine Code

M178

[MB‑VERIFIED]

Peak Enquiry Season

Summer — performance car season exposes boost and cooling issues

[PATTERN DATA]

Regional Demand

London25%

South East22%

South West15%

PATTERN DATA

Regional Demand Breakdown

25%London

22%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.

Find the best Mercedes‑AMG GT engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and keep your AMG V8 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