What are the common problems with the Mercedes G350d?

The most frequently reported issues are DPF clogging and AdBlue system faults (persistent pressure sensor errors, especially with city driving), fuel system issues (Bosch CP4 injectors sensitive to fuel quality), turbocharger faults (oil deposits, actuator issues, boost lag), Camtronic camshaft rocker wear (popping intake noise), and wiring harness chafing (recall for potential damage to ABS/ESP systems).

Is it worth replacing a Mercedes G350d engine, or should I scrap the car?

Depends on vehicle value. Against a well-kept £80,000 G350d, a £7,000 recon is 9% — definitely worth it. Against a high-mileage £35,000 example, the same recon approaches our 70% Mercedes threshold — get a scrap valuation first.

How do I find my Mercedes G350d engine code?

Listed on the VIN plate and vehicle documentation. The G350d carries the engine code OM656 D29 R SCR. It's a 2.9-litre straight-six twin-turbo diesel engine used in the G-Class W463 from 2019 onwards. The badge on the tailgate is the easiest tell — 'G 350 d'.

Can I repair the DPF issues on the G350d, or does it need full engine replacement?

DPF issues are usually repairable without engine replacement. However, owners report persistent DPF pressure sensor failures even after replacing the DPF and sensors. If you experience recurring DPF issues, ensure you're using the correct low-ash oil, taking regular motorway runs for regeneration, and having the vehicle properly diagnosed with STAR diagnostic equipment. In some cases, the underlying cause may be EGR or wiring faults rather than the DPF itself. If DPF issues are ignored, they can lead to more serious engine damage.

Mercedes G350d2019–present2.9L Straight-Six Twin-Turbo Diesel (OM656)

Mercedes G350d Engine Replacement — Compare Prices & Get Quotes

Name: Mercedes G350d UK Engine Enquiry Data 2025
Creator: MercedesEngine.uk

Get quotes today from trusted UK Mercedes G-Class specialists. Compare reconditioned, rebuilt and used OM656 2.9-litre straight-six twin-turbo diesel engines — the most powerful diesel G-Class ever — supply & fit available nationwide.

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Mercedes G350d Engines — from £3,500 to £9,500Code: OM656

Mercedes G350d Engines — from £3,500 to £9,500· Code: OM656

Instant QuotesNo Obligation100% FreeReconditionedRebuiltUsedSupply & Fit AvailableUK-Wide Network

The G350d THROUGH TIME — Era Map

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

Era Note

One engine throughout this badge's history — no era ambiguity.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

W463 G350d BMW 320d W463 G350d

2019–presentOM656 (2.9L Straight-Six Twin-Turbo Diesel)★★★★☆ [NEWLY ASSIGNED — see Data Note]£5,500–£8,500 [PLACEHOLDER — confirm vs cost sheet]One engine throughout this badge's history — no era ambiguity.

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 G350d Engine Replacement Costs

Supply Only£5,500–£8,500

Fitted (Indie)£6,800–£10,000

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£3,500–£5,500£4,800–£7,2001–6 monthsBudget priority; lower-mileage examples

Reconditioned Engine£5,500–£8,500£6,800–£10,00012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£6,500–£9,500£7,800–£11,00012–24 monthsLong-term ownership; 3+ year horizon

Main Dealer New£10,000–£14,000+£11,500–£16,000+24–36 monthsInsurance jobs, warranty claims

Figures above reflect the OM656 2.9-litre straight-six diesel engine. A full engine replacement can run anywhere between £1,500 and £5,000 on average, with Mercedes engine replacements typically around £3,500 or more. Used OM656 engines are available from approximately £3,500–£5,500.

Labour estimate: Fitting a G350d engine typically takes 16–22 hours at £75–£110/hr (independent) or £130–£180/hr (London/SE dealer). The G-Class's ladder-frame chassis and tight engine bay make this a complex job.

→ Compare G350d engine prices from UK specialists

Common Problems

1. DPF Clogging & Emissions System Faults

Symptoms: Engine warning light, DPF pressure sensor errors, loss of power, sluggish response, failed regeneration cycles, AdBlue system warnings.

Typical mileage: 30,000–60,000 miles (urban-driven vehicles)

Repair cost: £500–£2,000 (DPF clean, sensor replacement, or AdBlue system repair)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £5,500–£9,500 (if emissions system damage leads to engine issues)

🟡 Monitor - book inspection soon

Our recommendation:

The G350d's DPF and AdBlue systems are sensitive to short urban journeys. Owners report persistent DPF pressure sensor failures even after replacing the DPF and sensors. One owner experienced the check engine light recurring with the same DPF pressure sensor failure after multiple replacements and forced regenerations. If you predominantly drive in town, ensure the vehicle completes regular regeneration cycles — a motorway run at 2,000+ rpm for 20 minutes at least once a week is recommended. Using the correct low-ash oil is critical for DPF longevity.

Read the full DPF failure guide

1. DPF Clogging & Emissions System Faults

Symptoms: Engine warning light, DPF pressure sensor errors, loss of power, sluggish response, failed regeneration cycles, AdBlue system warnings.

Typical mileage: 30,000–60,000 miles (urban-driven vehicles)

Repair cost: £500–£2,000 (DPF clean, sensor replacement, or AdBlue system repair)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £5,500–£9,500 (if emissions system damage leads to engine issues)

🟡 Monitor - book inspection soon

Our recommendation:

Read the full DPF failure guide

2. Fuel System Sensitivity — Bosch CP4 Injector Issues

Symptoms: Rough running, misfires, poor acceleration, engine warning light, increased fuel consumption.

Typical mileage: 40,000–80,000 miles

Repair cost: £600–£2,000 (injector replacement — up to six piezo injectors)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £5,500–£9,500 (if fuel system damage leads to engine failure)

🟡 Monitor - book inspection soon

Our recommendation:

The OM656 uses a Bosch CP4 common-rail system with sensitive piezo injectors. It does not tolerate poor-quality diesel or contamination. Even minor impurities in the fuel tank can damage the injectors, while a clogged fuel filter disrupts combustion and leads to power loss. Regular fuel filter changes and the use of high-quality diesel can significantly extend engine life.

Read the full fuel injector failure guide

3. Turbocharger & Camtronic Valve Timing Issues

Symptoms: Loss of power, unusual noises from the engine bay (whistling, grinding), turbo lag, popping noise from the intake manifold, engine warning light.

Typical mileage: 40,000–80,000 miles

Repair cost: £800–£2,500 (turbocharger repair; Camtronic rocker/actuator replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £5,500–£9,500 (if left untreated leads to engine damage)

🟠 Check - book inspection urgently

Our recommendation:

The OM656's BorgWarner R2S turbocharger is a sensitive component. Oil deposits, worn bearings, or a contaminated charge air system can lead to power loss and unusual noises. A known turbo actuator issue involves a hose that gets too hot and collapses, causing boost faults. Cam rocker wear is also a known issue on the OM656 — it will show up as a popping sound in the intake. If you notice unusual noises or loss of power, have the turbocharger and Camtronic system inspected immediately.

Read the full turbocharger failure guide

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G350d — 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.

G350d — 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 SenseDPF clogging✅ Yes£500–£2,000Regular regeneration and quality oil prevent issuesFuel injector issues (CP4 system)✅ Yes£600–£2,000Use quality fuel and regular filter changesTurbocharger faults✅ Yes£800–£2,500Early detection prevents engine damageCamtronic cam rocker wear✅ Yes£800–£2,500Catch it early before cam lobe scoring occursWiring harness chafing (recall)✅ YesFree under recallCheck if your vehicle is affectedMajor internal engine failure❌ Usually No£5,500–£9,500Typically requires full engine replacement or complete rebuild

Buying This G350d? Check These First

Buy If

Full Mercedes service history with evidence of regular oil changes using MB 229.5 or 229.51 spec oil
DPF and AdBlue system regularly maintained (regular motorway runs)
Camtronic system inspected (no popping intake noises)
Turbocharger and fuel system inspected
Wiring harness recall completed (if applicable)

Avoid If

Persistent DPF warning lights with no resolution
Popping noise from the intake (cam rocker wear warning)
Loss of power or turbo lag (turbo or actuator issues)
Poor service history — the OM656 is a sophisticated engine that demands good maintenance

Closing Verdict

The G350d is powered by Mercedes' modern OM656 straight-six diesel — a sophisticated and refined engine that delivers exceptional performance and efficiency. It's the most powerful diesel G-Class ever, producing 286 hp and 600 Nm of torque. It also achieves the best fuel economy of any G-Class. The engine is generally reliable, but it has known weak points: DPF/AdBlue system issues (especially with city driving), Bosch CP4 fuel system sensitivity, turbocharger concerns, Camtronic valve timing issues, and a wiring harness recall. These are well-understood and manageable with proper maintenance. Buy on documented history, not on faith. A well-maintained G350d is a £70,000–£100,000 luxury off-roader; a neglected one is a £7,000 engine replacement waiting to happen.

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

→ Compare G350d engine prices before you buy

Don't Guess. Compare.

Get real quotes from vetted UK specialists and make the right call for your 320d.

→ Compare G350d engine prices before you buy

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Buying Checklist

Before you buy a used Mercedes G350d (or before you commit to an engine replacement), check these:

Cold Start — Listen for popping noises from the intake (cam rocker wear warning)

Service History — including the OM656 era (2019–present) and confirmed oil-change intervals using MB 229.5/229.51 spec oil

DPF/AdBlue Check — Any DPF or AdBlue warning lights or regeneration issues? (city driving is high risk)

Fuel System Check — Evidence of regular fuel filter changes and quality fuel use

Turbo Check — Any loss of power, turbo lag, or unusual noises? (turbo or actuator warning)

Wiring Harness Check — Has the wiring harness recall been completed? (potential chafing issue)

Engine Warning Light — Have codes been read? Any unresolved DPF, fuel, turbo, or Camtronic 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.

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

Technical Specs

OM656

Displacement2,925 cc

CylindersStraight-6, 4 valves per cylinder

Bore x Stroke82.0 mm × 92.4 mm

Compression Ratio15.5:1

Fuel SystemCommon-rail direct injection (Bosch CP4 with piezo injectors)

TurbochargerBorgWarner R2S sequential twin turbochargers

ValvetrainDOHC with Camtronic variable valve timing

BlockAluminium with plasma-sprayed cast iron Nanoslide coating

Transmission9G-Tronic 9-speed automatic

→ Compare G350d engine prices for your Mercedes

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Market Intelligence

Most Common Failure

DPF/AdBlue system issues — persistent pressure sensor failures are frequently reported, especially with city driving

Average Enquiry Mileage

30,000

–60,000 miles

[PATTERN DATA]

Average Replacement Cost

£5,500

–£8,500 reconditioned, supply only

[PLACEHOLDER — confirm vs cost sheet]

Most Requested Engine Code

OM656 (G350d)

[PATTERN DATA]

Peak Enquiry Season

Winter — cold starts expose Camtronic and DPF issues【PATTERN DATA】

Regional Demand

London22%

South East18%

South West15%

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.

Why UK Mercedes G350d Owners Trust MercedesEngine.uk

Trusted G350d Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real G-Class owners, as part of the Engine Finders network, covering the entire OM656 era from 2019 to the present day.
Compare G350d Engine Replacement Companies
see prices, warranty terms and supply & fit options side-by-side before you commit, across every W463 that left the factory with the 2.9-litre straight-six diesel.
UK Engine Replacement Services for G350d
supply-only or full supply & fit available nationwide, covering the full W463 production run — and we're vetted across every era of this badge.

Find the best Mercedes G350d engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get your G-Class back on the road with confidence.

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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