How much does a Mercedes-Benz G55 AMG engine replacement cost in the UK?

A reconditioned M113K engine typically costs £4,500–£8,500 supply only, with used units available from £1,800–£4,000. Rebuilt engines from specialist suppliers start at around £6,995. Fitting adds £2,000–£3,500 depending on the workshop. Use our calculator for a figure specific to your G55.

Is the Mercedes-Benz G55 AMG engine reliable?

Yes — the M113K is widely regarded as 'pretty much bulletproof in stock form' and 'one of the most robust German performance engines'. Examples have been documented exceeding 246,000 miles. The main issues are the intercooler pump (a common wear item), oil leaks, and timing chain tensioner wear at high mileage. In stock form, it's one of the most reliable AMG V8s ever built.

What are the common problems with the Mercedes-Benz G55 AMG?

Intercooler pump failure (causes supercharger shutoff after hard acceleration — replace with upgraded Bosch A000 500 03 86 or Johnson CM30 pump), oil leaks from valve cover gaskets and oil cooler seals, timing chain tensioner wear at higher mileages, and supercharger clutch 'chirp'. The engine is fundamentally robust.

Is it worth replacing a Mercedes-Benz G55 AMG engine, or should I scrap the car?

G55 AMG values remain strong — a well-kept example is often worth £20,000–£50,000+. A £4,500–£8,500 reconditioned engine is 10–30% of the vehicle's value — apply the Mercedes 70% scrap threshold. If the car is a cherished example, replacement is almost always worthwhile. The G55's iconic status and rising values make engine replacement a sound investment.

How do I find my Mercedes-Benz G55 AMG engine code?

The engine code is M113K (M113.982) — it's the only 5.4-litre supercharged V8 used in the G55 AMG. You can find it on the VIN plate, in the vehicle documentation, or on a label on the engine itself. Production ran from 2004 to 2011.

Can I repair the M113K timing chain, or does the engine need replacement?

The timing chain and tensioner can be replaced — they are wear items. Replacement costs £1,500–£3,500 and is a labour-intensive job. If the chain fails and jumps timing, the engine is typically destroyed. A preventative tensioner replacement is far cheaper than a full engine replacement (£4,500+). At the first sign of rattling or slapping from the front of the engine, book an inspection immediately.

Mercedes-Benz G55 AMG2004–20115.4-litre Supercharged V8

Mercedes-Benz G55 AMG Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes-Benz G55 AMG UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

The G55 AMG is powered by the legendary M113K 5.4-litre supercharged V8 — hand-built, utterly bombproof, and delivering 500 hp of brutal, old-school AMG character. It's one of the most robust performance engines ever made, but supercharger pumps, oil leaks and cooling system components are well-documented with age. Get quotes from UK specialists for reconditioned, rebuilt and used units today.

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Supply & Fit Available

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Mercedes-Benz G55 AMG Engines — from £1,800 to £8,500Code: M113K

Mercedes-Benz G55 AMG Engines — from £1,800 to £8,500· Code: M113K

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The G55 AMG THROUGH TIME — Era Map

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

GenerationYearsEngine CodeReliabilityRecon CostEra Note

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 G55 AMG Engine Replacement Costs

Supply Only£4,500–£8,500

Fitted (Indie)£6,500–£10,500

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£1,800–£4,000£3,500–£6,0001–6 monthsBudget priority; lower‑mileage examples

Reconditioned Engine£4,500–£8,500£6,500–£10,50012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£6,500–£10,000+£8,500–£12,500+12–24 monthsLong‑term ownership; 3+ year horizon

Main Dealer New£10,000–£15,000+£12,000–£18,000+24–36 monthsInsurance jobs, warranty claims

Figures above reflect the current G55 AMG market. Reconditioned engines from specialist suppliers start at around £6,995 for rebuilds, with fully reconditioned units typically ranging from £4,500–£8,500. The M113K is relatively affordable to replace compared to newer AMG V8s, thanks to its widespread use across multiple models and strong aftermarket support.

Labour estimate: Fitting a G55 AMG engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). The G-Wagen's body-on-frame construction makes engine access surprisingly straightforward compared to other AMG models.

→ Compare G55 AMG engine prices from UK specialists

Common Problems

1. Intercooler Pump Failure — The "Supercharger Shutoff"

Symptoms: Huge loss of power after 1–2 hard accelerations, supercharger shuts off for 30 seconds to 1 minute, sluggish performance, feeling of reduced power

Typical mileage: 40,000–100,000 miles

Repair cost: £200–£500 (intercooler pump replacement)

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently

Our recommendation:

The intercooler circulation pump is the single most common failure on the M113K. The original pumps fail frequently — many owners are on their third pump. The pump is responsible for circulating coolant through the intercoolers to keep intake air temperatures down. When it fails, the ECU detects rising intake temperatures and shuts off the supercharger to protect the engine. The upgraded Bosch pump (part number A000 500 03 86) is the recommended replacement. Many owners also upgrade to the Johnson CM30 pump for improved reliability and cooling performance.

Read the full intercooler pump failure guide

1. Intercooler Pump Failure — The "Supercharger Shutoff"

Symptoms: Huge loss of power after 1–2 hard accelerations, supercharger shuts off for 30 seconds to 1 minute, sluggish performance, feeling of reduced power

Typical mileage: 40,000–100,000 miles

Repair cost: £200–£500 (intercooler pump replacement)

Replacement cost: N/A — repair only

🟠 Check - book inspection urgently

Our recommendation:

Read the full intercooler pump failure guide

2. Oil Leaks — Valve Cover Gaskets and Oil Cooler Seals

Symptoms: Oil spots under the car, burning oil smell from the engine bay, visible oil residue on the engine block, low oil level warning

Typical mileage: 60,000–150,000 miles

Repair cost: £300–£1,200 (gasket and seal replacement)

Replacement cost: N/A — repair only

🟡 Monitor - book inspection soon

Our recommendation:

The M113K is known for oil leaks, particularly from valve cover gaskets, the oil cooler gasket, and the oil pressure test port. These leaks are rarely catastrophic but should be addressed to prevent oil loss and potential fire hazards. Replacing valve cover gaskets is a routine job for any Mercedes specialist. Check for oil residue around the valve covers regularly and investigate any unexplained oil consumption.

Read the full oil leak guide

3. Timing Chain Tensioner and Guide Wear

Symptoms: Rattling or slapping noise from the front of the engine, especially on cold start or acceleration, metallic ticking

Typical mileage: 100,000–200,000 miles

Repair cost: £1,500–£3,500 (timing chain, tensioner and guide replacement)

Replacement cost: £4,500–£8,500 (if chain jumps and causes valve interference)

🟠 Check - book inspection urgently

Our recommendation:

While the M113K's timing chain is generally robust, it can stretch over time. The tensioner is a known wear item. If the chain jumps, piston-valve contact is likely, destroying the engine. One owner reported that a failed $1 rubber o-ring on the front timing cover after a water pump replacement allowed coolant to mix with oil, causing engine failure — a "rare show stopper that ruins motors". If you hear rattling from the front of the engine, have the timing chain inspected immediately. A preventative tensioner replacement is far cheaper than a full engine replacement.

Read the full timing chain failure guide

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G55 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.

G55 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 SenseIntercooler pump failure✅ Yes£200–£500Simple replacement — the most common M113K issueOil leaks (valve covers, oil cooler)✅ Yes£300–£1,200Well-understood job — catch before oil starvationTiming chain tensioner (preventative)✅ Yes£1,500–£3,500Labour-intensive but far cheaper than a full engine replacementTiming chain failure (engine damage)❌ Usually NoEngine replacementIf chain jumps and valves hit pistons, replacement is the only optionSupercharger clutch wear✅ Yes£500–£1,500Clutch pack replacement — the "chirp" fixHead gasket failure (rare)⚠️ Sometimes£2,000–£4,000Viable on a cherished example; rare on the M113K

Buying This G55 AMG? Check These First

Buy If

Evidence of intercooler pump replacement (upgraded Bosch or Johnson pump) — the most common failure addressed
Full service history with regular oil changes (every 5,000–10,000 miles) — the M113K rewards good maintenance
No rattling from the front of the engine — timing chain tensioner should be healthy
A well-maintained example — the M113K is "pretty much bulletproof in stock form"

Avoid If

Any rattling or slapping from the front of the engine — timing chain tensioner wear is likely
Evidence of repeated coolant top-ups without a diagnosed leak — head gasket or cooling system issues
Poor service history — the M113K is robust but not invincible
Modified examples without supporting engine work — modified M113Ks have been known to "blow up"

Closing Verdict

The M113K is one of the most robust and characterful engines AMG ever built — a "bulletproof", hand-built 5.4-litre supercharged V8 that delivers old-school AMG charm in a boxy off-road icon. Its weaknesses are well-understood: the intercooler pump (replace with the upgraded unit), oil leaks from valve covers and oil cooler seals, and timing chain wear at high mileage. Buy on history, maintain on schedule, and the G55 AMG will reward you with one of the most charismatic driving experiences of any vehicle ever made. It is "one of the most robust German performance engines" and, when stock, "pretty much bulletproof".

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

→ Compare G55 AMG engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes-Benz G55 AMG (or before you commit to an engine replacement), check these:

1. Intercooler Pump — Any history of replacement? (the most common M113K failure — check for upgraded Bosch A000 500 03 86 or Johnson CM30 pump)

2. Cold Start — Listen for rattles or slapping from the front of the engine (timing chain tensioner warning)

3. Service History — including evidence of regular oil changes and major maintenance

4. Oil Leaks — Any oil under the car or around the valve covers? (common M113K issue)

5. Coolant Level — Any unexplained loss? (head gasket or cooling system warning)

6. Supercharger Clutch — Any "chirp" noise? (clutch pack wear — common and harmless but indicates wear)

7. Engine Warning Light — Have codes been read? Any unresolved issues?

8. MOT History — Check for emissions-related failures (catalyst, O2 sensors)

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 — one engine throughout this badge's production run.

M113K (M113.982)

Years2004–2011

Power500 hp / 516 lb-ft

2025 Enquiries[PATTERN DATA]

Avg. Recon Cost£4,500–£8,500 [MB-QUOTE]

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M113K (M113.982)2004–2011500 hp / 516 lb-ft[PATTERN DATA]£4,500–£8,500 [MB-QUOTE]

Technical Specs

M113K — 5.4 Kompressor V8

Displacement5,439cc (5.4‑litre)

CylindersV8, 90° configuration

ConstructionAll-aluminium block and heads

Compression Ratio9.0:1

Fuel SystemMulti-point fuel injection (ME 2.8)

SuperchargerBelt-driven Lysholm-type supercharger with dual intercoolers

ValvetrainSOHC, 3 valves per cylinder

Transmission5-speed automatic (5G-Tronic)

DrivePermanent 4MATIC all-wheel drive

→ Compare G55 AMG engine prices for your Mercedes

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Market Intelligence

Most Common Failure

Intercooler pump failure — the defining issue on the M113K; causes supercharger shutoff after hard acceleration

Average Enquiry Mileage

60,000

–120,000 miles【PATTERN DATA】

Average Replacement Cost

£4,500

–£8,500 reconditioned, supply only【MB-QUOTE】

Most Requested Engine Code

M113K — the legendary 5.4-litre supercharged V8【PATTERN DATA】

Peak Enquiry Season

Spring — off‑road and performance SUV season【PATTERN DATA】

Regional Demand

London22%

South East18%

South West (14%)【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.

Trusted G55 AMG Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real G55 AMG owners, as part of the Engine Finders network, across the legendary M113K generation.
Compare G55 AMG Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit, with specialists who genuinely understand the M113K's intercooler pump, oil leak and timing chain nuances.
UK Engine Replacement Services for G55 AMG
supply‑only or full supply & fit available nationwide, covering Mercedes-AMG's most iconic off‑road V8 with a 12‑month warranty as standard.

Find the best Mercedes-Benz G55 AMG engine replacement UK owners trust. Compare prices from trusted specialists on MercedesEngine.uk today and keep your G-Wagen performing at its best.

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12-Month Warranty

As standard

Nationwide Delivery

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