Mercedes Benz GLC Class GLC43 Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK Mercedes Benz GLC Class GLC43 AMG engine specialists. Compare prices on reconditioned, rebuilt and used engines for the twin-turbo V6 - supply & fit available nationwide.
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Clear information first, then the right engine and specialist for your exact vehicle.
Variant History
Mercedes Benz GLC Class GLC43 Engine History & Specs at a Glance
The GLC43 AMG joined the GLC range in 2016 as the performance entry point below the V8-powered GLC63. Powered by the M276 3.0-litre twin-turbo V6, it delivered 367hp and a characterful AMG soundtrack. In 2024, the second-generation X254 GLC43 replaced the V6 with the M139l 2.0-litre four-cylinder featuring an electrically assisted turbocharger and 48V mild-hybrid system - more power, fewer cylinders, and a dramatically different character.
M139l, 2.0L turbo four-cylinder with electric turbocharger and 48V mild hybrid, 416hp (X254 GLC43)
Every engine fitted to the Mercedes Benz GLC Class GLC43 is covered below, with UK rebuilt pricing and known failure points - from M276 camshaft adjuster wear to M139l electric turbocharger reliability.
Engine Codes & Pricing
Mercedes Benz GLC Class GLC43 Engine Codes Specifications & Replacement Cost
Find your exact engine code, specs and UK replacement cost guide.
M276.823 — 3.0L Twin-Turbo V6 (2016-2022)
Power Output
367 hp (270 kW) @ 5,500-6,000 rpm (2016-2019); 390 hp (287 kW) @ 5,500-6,100 rpm (2019-2022)
Mercedes Benz GLC Class GLC43 Engine Problems Repair Cost vs Replacement
The GLC43's M276 twin-turbo V6 is widely regarded as one of Mercedes' most reliable modern engines, but it has one well-documented Achilles' heel - camshaft adjuster wear that manifests as a cold-start rattle. The newer M139l four-cylinder is too recent for definitive failure data, but its complexity (electric turbocharger, 48V system) introduces new potential failure points. Every rebuilt engine supplied through EnginesMarket includes upgraded components addressing the original failure point, plus a minimum 12-month unlimited-mileage warranty.
Common failure points and repair options
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M276 Camshaft Adjuster (Phaser) Failure
Affected
Mercedes GLC43 AMG 4MATIC (M276.823, 2016-2022)
Typical failure mileage
50,000-90,000 miles
Root cause
The intake camshaft adjusters (phasers) can break internally, causing the timing to drift. A metallic rattling noise on cold start is the classic symptom. If ignored, incorrect cam phasing can cause poor combustion, rough idle, misfires, and accelerated timing chain wear.
Full Replacement - Rebuilt M276 engine with revised adjusters
£9,000-£14,000
£6,000-£8,500
Our recommendation
The M276 is a £25,000-£40,000 car at current market values. If the rattle has just started with no metal in the oil or fault codes, the intermediate adjuster replacement is the value play - find a specialist who has done this job before. If the engine has been run with adjuster failure to the point of camshaft pulse wheel damage or codes persist after adjuster replacement, step up to a full rebuilt unit from an AMG specialist. Never use non-OEM adjusters on this engine - they fail within 10,000 miles.
The M276 can develop oil leaks from the front upper timing covers and camshaft position sensors. These leaks are not catastrophic but can lead to oil contamination of electrical components and, if ignored, low oil pressure.
Repair options
Repair tier
Dealer price
Specialist price
Minor - Camshaft sensor seal replacement
£400-£700
£250-£450
Intermediate - Upper timing cover reseal
£1,200-£1,800
£800-£1,200
Full Replacement - Rebuilt M276 engine
£9,000-£14,000
£6,000-£8,500
Our recommendation
Oil leaks on the M276 are common but not usually urgent. If you notice oil on the undertray or a burning smell, have a specialist inspect the timing covers and camshaft sensors. The sensor seals are a straightforward fix; timing cover resealing is more labour-intensive but worthwhile if the car is otherwise healthy. Don't ignore persistent leaks - oil starvation is the quickest way to destroy an otherwise robust M276.
M139l Electric Turbocharger & 48V System Reliability (2024-present)
Affected
Mercedes GLC43 AMG 4MATIC (M139l, 2024-present)
Typical failure mileage
Unknown - too early for data
Root cause
The M139l features an F1-derived electrically assisted turbocharger and a 48V mild-hybrid system. While these technologies promise better responsiveness and efficiency, they introduce additional complexity and potential failure points not present on the older V6.
Repair options
Repair tier
Dealer price
Specialist price
Minor - 48V battery replacement
£800-£1,500
£500-£900
Intermediate - Electric turbocharger replacement
£2,500-£4,000
£1,800-£3,000
Full Replacement - Rebuilt M139l engine
£10,000-£15,000
£7,500-£11,000
Our recommendation
The M139l is too new for definitive reliability data. Early owner feedback is mixed - the engine delivers strong performance but the 48V system and electric turbocharger add complexity. If you're considering a GLC43, ensure the 48V battery health is checked and that the vehicle has a comprehensive warranty. For owners facing issues, specialist diagnostics are essential - not all independent workshops are equipped for M139l work.
Don't Let Camshaft Adjuster Rattle or Electric Turbo Complexity Write Off Your Mercedes GLC43
Whether you're facing M276 camshaft adjuster wear on your V6 GLC43 or considering the long-term reliability of the new M139l four-cylinder, EnginesMarket makes it simple to compare quotes from trusted UK Mercedes AMG specialists. Every rebuilt engine in our network carries upgraded components addressing the original design weakness - plus a minimum 12-month unlimited mileage warranty with nationwide delivery and supply & fit options. Don't pay main dealer premiums. Compare prices from independent AMG specialists who know these performance engines inside out.
Short summary: A 1-3 second metallic rattling noise on cold start is the classic warning sign on the M276 V6. If ignored, it can lead to rough idle, misfires, check engine lights, and eventually catastrophic engine failure.
Cold start rattle that disappears after oil pressure builds - earliest warning
Short summary: Yes - the M276 is widely regarded as one of the most reliable Mercedes engines of the last 20 years. The camshaft adjuster issue is the only significant weak point, and it's well understood by specialists. With proper maintenance, the M276 routinely exceeds 150,000 miles.
M276 is considered "the most reliable MB engine in at least 20 years"
Camshaft adjuster wear is the dominant failure - catch it early
Oil leaks from timing covers and camshaft sensors are common but not catastrophic
Regular oil changes (every 10,000 miles) are essential - use MB 229.5 spec oil
Short summary: Properly maintained M276 V6 engines routinely reach 150,000-200,000 miles before major work. The M139l four-cylinder is too new for definitive long-term data, but early indications suggest similar longevity with proper maintenance.
M276 (2016-2022): 150,000-200,000 miles with regular servicing
M139l (2024-present): too early for definitive data - reliability unproven
Service interval is 10,000 miles or 12 months - use Mercedes-spec oil
Late oil changes accelerate camshaft adjuster wear and timing chain stretch
Short summary: Yes, if the GLC43 is otherwise in good condition with no rust or major electrical faults. A rebuilt M276 costs £4,500-£8,000 - far less than replacing a £25,000-£40,000 vehicle. The GLC43's strong residual values make engine replacement financially justifiable.
GLC43 values: £25,000-£40,000 depending on year, mileage and condition
Rebuilt engine with upgraded components fixes original weak points
Supply & fit typically £6,000-£10,000 depending on engine code
New engine includes 12-month unlimited mileage warranty
Short summary: The 2016-2022 GLC43 uses the M276 3.0L twin-turbo V6 (367-390hp) with a characterful AMG soundtrack. The 2024-present GLC43 uses the M139l 2.0L turbo four-cylinder with electric turbocharger and 48V mild hybrid (416hp) - more power, fewer cylinders, and a very different character.
Compare Mercedes GLC Class GLC43 Engine Prices Today
Comparing quotes for your Mercedes GLC43 AMG is completely free, with no obligation and no pressure. Enter your registration above to get tailored quotes from UK Mercedes AMG specialists who understand the M276 V6 and M139l four-cylinder inside out. Whether you need a used engine, a reconditioned unit, or a full rebuilt engine with upgraded camshaft adjusters, we'll connect you with the right specialist for your exact GLC43 - with a minimum 12-month warranty on every engine supplied.
200+200+ AMG engines supplied through our network
12-Month12-Month Warranty on every rebuilt GLC43 engine
Compare quotes from trusted UK Mercedes Benz GLC Class GLC43 engine specialists with warranty-backed rebuilt, reconditioned and used options nationwide.