Engines Market

Mercedes GLC 300d Specialists

Mercedes Benz GLC Class GLC 300d Engine Replacement Compare Prices & Get Quotes

Get quotes today from trusted UK Mercedes Benz GLC Class 300d engine specialists. Compare prices on reconditioned, rebuilt and used OM654 2.0-litre diesel engines - supply & fit available nationwide for both rear-wheel drive and 4MATIC variants.

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Mercedes Benz GLC Class GLC 300d Engine
from£2,800 to £4,800
  • Usedfrom £1,800
  • Reconditionedfrom £2,400
  • Common codesOM654.920, OM654.820
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How it works

3 Simple Steps to Finding the Right Replacement Engine

Clear information first, then the right engine and specialist for your exact vehicle.

Variant History

Mercedes Benz GLC Class GLC 300d Engine History & Specs at a Glance

The Mercedes Benz GLC 300d arrived with the 2019 X253 facelift, introducing the all-new OM654 2.0-litre modular diesel engine to the GLC range - replacing the older OM651 2.1-litre unit with a lighter, more efficient and more refined powertrain that delivered 245hp and 500Nm of torque [0†L27-L28].

Mercedes Benz GLC Class GLC 300d
  1. 2019

    GLC 300d launched with X253 facelift, OM654 2.0L turbo diesel, 245hp, 500Nm, 9G-Tronic automatic transmission

  2. 2019

    OM654 introduced stepped bowl combustion and reduced friction for Euro 6d compliance

  3. 2022

    X254 second-generation GLC launched, GLC 300d upgraded to OM654.820 with 269hp and mild hybrid 48V system [6†L20-L21]

  4. 2023

    GLC 300d continues in X254 range with refined emissions and improved efficiency

Every OM654 diesel engine fitted to the Mercedes Benz GLC Class 300d is covered below, with UK rebuilt pricing and known failure points from real owner experience.

Engine Codes & Pricing

Mercedes Benz GLC Class 300d Engine Codes Specifications & Replacement Cost

Find your exact engine code, specs and UK replacement cost guide.

OM654.920 — 2.0L Diesel (2019-2022) engine

OM654.920 — 2.0L Diesel (2019-2022)

Power Output
245 hp (180 kW) @ 4,200 rpm
Torque
500 Nm @ 1,600-2,600 rpm [0†L12-L13]
Displacement
1,950cc
Configuration
Inline-4, DOHC, twin-stage turbocharger, common-rail direct injection
Years Fitted
2019-2022

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Common Problems

Mercedes Benz GLC Class 300d Engine Problems Repair Cost vs Replacement

The Mercedes Benz GLC 300d relies on the OM654 2.0-litre modular diesel - a lightweight, all-aluminium engine praised for refinement and efficiency, but not without its vulnerabilities. EGR cooler cracking, NOx sensor failure, rocker arm bearing wear, and timing chain issues dominate replacement demand. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address the original failure point - plus a minimum 12-month unlimited mileage warranty. Below we break down the most common GLC 300d engine failures, what they cost to fix, and when replacement is the smarter financial decision.

Common failure points and repair options

OM654 EGR Cooler Cracking

Affected
Mercedes Benz GLC Class GLC 300d (OM654.920, OM654.820, 2019-present)
Typical failure mileage
40,000 - 80,000 miles
Root cause
The original EGR cooler (part A6540940101) suffers thermal stress fractures, allowing coolant to enter the exhaust system, triggering low coolant warnings, misfires, and eventually engine overheating. Coolant loss without a visible external leak is often the first sign of EGR cooler failure.

Repair options

Repair tierDealer priceSpecialist price
Minor - EGR Cooler Replacement£1,100-£1,600£700-£1,100
Intermediate - Cooler Plus Intake Cleaning£1,600-£2,300£1,000-£1,500
Full Replacement - Rebuilt Engine£6,500-£9,000£3,800-£5,800
Our recommendation
If caught early with no overheating damage, replace just the EGR cooler - specialist pricing beats dealer by 30-40%. However, many cases present after coolant loss has caused cylinder head damage. On a GLC 300d worth £18,000-£35,000, the full engine replacement with upgraded cooler is often the safer long-term investment.
-> Compare rebuilt OM654 prices for your Mercedes GLC 300d

OM654 NOx Sensor & AdBlue System Failure

Affected
Mercedes Benz GLC Class GLC 300d (OM654.920, OM654.820, 2019-present)
Typical failure mileage
30,000 - 60,000 miles
Root cause
NOx sensors fail due to internal heating element degradation, causing permanent emissions warning lights. AdBlue crystallises inside the injector nozzle, blocking flow and triggering countdown start inhibitors. These emissions system failures are a dominant driver of GLC 300d workshop visits.

Repair options

Repair tierDealer priceSpecialist price
Minor - AdBlue Injector Cleaning£250-£400£120-£200
Intermediate - NOx Sensor Pair Replacement£600-£1,000£350-£600
Major - AdBlue Injector & Dosing Module£900-£1,400£500-£800
Full Replacement - Rebuilt Engine£6,500-£9,000£3,800-£5,800
Our recommendation
For a GLC 300d still under 60,000 miles, replace the AdBlue injector and NOx sensors individually as they fail - but always replace both NOx sensors as a pair (upstream and downstream) to avoid repeat workshop visits. If emissions warnings persist after component replacement, have the entire SCR system inspected before committing to further repairs.
-> Compare OM654 emissions repair quotes for your GLC 300d

OM654 Rocker Arm Bearing & Timing Chain Wear

Affected
Mercedes Benz GLC Class GLC 300d (OM654.920, OM654.820, 2019-present)
Typical failure mileage
60,000 - 120,000 miles
Root cause
The OM654 has a documented issue with failing rocker arm bearings and damaged camshaft lobes. Timing chain wear causing rattle on cold start has also been reported. These issues typically manifest on higher-mileage examples and can lead to catastrophic engine failure if ignored.

Repair options

Repair tierDealer priceSpecialist price
Minor - Rocker Arm & Bearing Inspection£400-£700£250-£450
Intermediate - Camshaft & Rocker Assembly£2,000-£3,500£1,200-£2,000
Major - Full Timing Chain & Valve Train Set£3,500-£5,000£2,000-£3,200
Full Replacement - Rebuilt Engine£6,500-£9,000£3,800-£5,800
Our recommendation
The OM654's rocker arm bearing failure can appear with minimal warning. If you hear unusual tapping or ticking from the engine, have the valve train inspected immediately. On higher-mileage GLC 300d examples (80,000+ miles), a full rebuilt engine with upgraded valve train components eliminates all common failure points in one go - often more cost-effective than piecemeal repairs.
-> Compare rebuilt OM654 Mercedes Benz GLC Class 300d engine prices

Don't Let Engine Failure Write Off Your Mercedes Benz GLC 300d

A failed OM654 engine doesn't have to mean the end of your GLC 300d. Whether you're dealing with EGR cooler cracking, NOx sensor failure, rocker arm bearing wear, or timing chain issues, EnginesMarket makes it simple to compare prices from trusted UK Mercedes Benz GLC Class specialists. Every rebuilt engine in our network includes upgraded components designed to address the original failure point, a minimum 12-month unlimited mileage warranty, and nationwide delivery with supply & fit options available.

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FAQ

Mercedes Benz GLC Class 300d Engine ReplacementFrequently Asked Questions

Everything Mercedes Benz GLC Class GLC 300d owners usually ask before choosing a rebuilt, reconditioned or used replacement engine.

Why Choose Us

Compare Mercedes Benz GLC Class 300d Engine Prices Today

Comparing quotes for your Mercedes Benz GLC Class 300d engine replacement is completely free and carries no obligation - enter your registration above, receive tailored prices from UK specialists who know the OM654 modular diesel engine inside out, and get back on the road with confidence. Every rebuilt engine is backed by a minimum 12-month unlimited mileage warranty.

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