Mercedes Benz GLC Class GLC63 Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK Mercedes Benz GLC Class GLC63 AMG engine specialists. Compare prices on reconditioned, rebuilt and used engines for the hand-built 4.0-litre twin-turbo V8 - supply & fit available nationwide.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £7,000 to £14,000
Used from £4,000 · Reconditioned from £6,500 · Common codes: M177.980
From £4,000
Tested, bare/short engine
From £6,500
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
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3 Simple Steps3 Simple Stepsto Finding the Best Mercedes Benz GLC Class GLC63 Replacement Engineto Finding the Best Mercedes Benz GLC Class GLC63 Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryMercedes Benz GLC Class GLC63 - Engine History & Specs at a Glance
The GLC63 AMG launched in 2017 as the flagship performance variant of the X253 GLC range. Powered by the hand-built M177 4.0-litre twin-turbo V8 - shared with the C63 and AMG GT - it held the title of the world's fastest SUV when it went on sale. In 2024, the second-generation X254 GLC63 replaced the V8 with a 2.0-litre four-cylinder plug-in hybrid producing 671hp - more power, but a very different character.
Variant HistoryMercedes Benz GLC Class GLC63 - Engine History & Specs at a Glance
The GLC63 AMG launched in 2017 as the flagship performance variant of the X253 GLC range. Powered by the hand-built M177 4.0-litre twin-turbo V8 - shared with the C63 and AMG GT - it held the title of the world's fastest SUV when it went on sale. In 2024, the second-generation X254 GLC63 replaced the V8 with a 2.0-litre four-cylinder plug-in hybrid producing 671hp - more power, but a very different character.
Mercedes Benz GLC Class GLC63
Fuel TypePetrol (M177: twin-turbo V8; M139l PHEV: turbo four-cylinder + electric motor)
Engine Size Range2.0L-4.0L (M177: 3,982cc; M139l: 1,991cc)
Power Output Range476-671hp across the variant's historyEngine History Timeline
M177.980 4.0L twin-turbo V8, 476hp (GLC63 4MATIC+, X253/C253)
M177.980 4.0L twin-turbo V8, 510hp (GLC63 S 4MATIC+, X253/C253)
Facelift X253/C253; M177 continues with 476hp and 510hp outputs unchanged
X253 GLC63 production ends; V8 discontinued
M139l PHEV 2.0L four-cylinder with plug-in hybrid, 671hp (X254 GLC63 S E Performance)
Key Specs Snapshot
Fuel TypePetrol (M177: twin-turbo V8; M139l PHEV: turbo four-cylinder + electric motor)Engine Size Range2.0L-4.0L (M177: 3,982cc; M139l: 1,991cc)Power Output Range476-671hp across the variant's historyYears Produced2017-2022 (V8); 2024-present (PHEV four-cylinder)Every engine fitted to the Mercedes Benz GLC Class GLC63 is covered below, with UK rebuilt pricing and known failure points - from M177 oil separator and rear main seal issues to M139l PHEV reliability questions.
Mercedes Benz GLC Class GLC63 Engine Codes - Specifications & Replacement CostMercedes Benz GLC Class GLC63 Engine Codes - Specifications & Replacement Cost
4.0L Twin-Turbo V8 (2017-2022)
Power Output476 hp (350 kW) @ 5,500-6,250 rpm (GLC63); 510 hp (375 kW) @ 5,500-6,250 rpm (GLC63 S)Torque650 Nm @ 1,750-4,500 rpm (GLC63); 700 Nm @ 1,750-4,500 rpm (GLC63 S)Years Fitted2017-2022Displacement3,982ccCylindersV8, 32-valve, DOHC, twin-turbocharged
Compatible Trim Levels
- GLC63 4MATIC+
- GLC63 S 4MATIC+
- GLC63 4MATIC+ Coupe
- GLC63 S 4MATIC+ Coupe
- GLC63 4MATIC+ Premium
- GLC63 S 4MATIC+ Premium Plus
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£4,000-£6,500
Reconditioned
Addressed known issues, tested
£6,500-£9,000
Rebuilt
Full teardown, upgraded internals
£7,000-£14,000
Common Failure
Oil separator failure leading to rear main seal leaks - the most frequent and expensive problem on the M177 as these vehicles accumulate mileage. Excessive crankcase pressure (positive or negative) forces oil past the rear main seal, causing oil dripping from the rear of the engine, oil around the transmission bellhousing, or a burning oil smell. Typical failure mileage: 40,000-80,000 miles.
The GLC63's M177 twin-turbo V8 is one of AMG's most impressive modern engines - a hand-built masterpiece that delivers serious power and performance. However, as these vehicles accumulate mileage, a small number of well-documented issues can drive significant repair costs. The most frequent and expensive problem is oil separator failure, which often leads to rear main seal leaks. Every rebuilt engine supplied through EnginesMarket includes upgraded components addressing the original failure point, plus a minimum 12-month unlimited-mileage warranty.
The Most Expensive M177 Problem
Affected Vehicles
Mercedes GLC63 AMG 4MATIC+ (M177.980, 2017-2022)
Typical Failure Mileage
40,000-80,000 miles
Root Cause
The oil separator (part of the crankcase ventilation system) fails, causing unbalanced crankcase pressure. Excessive positive pressure forces oil past engine seals, or excessive negative pressure (vacuum) pulls seals inward, distorting them. The rear main seal - sitting at the back of the crankshaft where the engine meets the transmission - is often the first to fail. Symptoms include oil dripping from the rear of the engine, oil around the transmission bellhousing, or a burning oil smell.
Why It Happens
The oil separator (part of the crankcase ventilation system) fails, causing unbalanced crankcase pressure. Excessive positive pressure forces oil past engine seals, or excessive negative pressure (vacuum) pulls seals inward, distorting them. The rear main seal - sitting at the back of the crankshaft where the engine meets the transmission - is often the first to fail. Symptoms include oil dripping from the rear of the engine, oil around the transmission bellhousing, or a burning oil smell.
Dealer (parts + labour)
£150-£300
Specialist (parts + labour)
£100-£200
What it involves
Check crankcase pressure, inspect oil separator, test oil cap vacuum
Suitability
Confirms whether separator or seal is the root cause
1 - 2 daysDealer (parts + labour)
£800-£1,200
Specialist (parts + labour)
£500-£800
What it involves
Replace oil separator, inspect crankcase ventilation system
Suitability
If caught before seal damage occurs
1 - 2 daysDealer (parts + labour)
£2,500-£4,000
Specialist (parts + labour)
£1,800-£2,800
What it involves
Replace rear main seal, drop transmission, inspect flywheel
Suitability
If seal has failed but no bottom-end damage
1 - 2 daysDealer (parts + labour)
£12,000-£18,000
Specialist (parts + labour)
£8,500-£14,000
What it involves
Supply & fit rebuilt M177 engine with upgraded oil separator, new rear main seal, full gasket set
Suitability
If oil loss has caused bearing or bottom-end damage
1 - 2 daysAll prices are indicative UK market ranges based on current UK specialist supplier data.| Repair Tier | Dealer (Parts + Labour) | Specialist (Parts + Labour) | What It Involves | Suitability | Estimated Time |
|---|---|---|---|---|---|
 Diagnosis - Oil separator check Minor | £150-£300 | £100-£200 | Check crankcase pressure, inspect oil separator, test oil cap vacuum | Confirms whether separator or seal is the root cause | 1 - 2 days |
 Intermediate - Oil separator replacement Best Value | £800-£1,200 | £500-£800 | Replace oil separator, inspect crankcase ventilation system | If caught before seal damage occurs | 1 - 2 days |
Major - Rear main seal replacement Best Value | £2,500-£4,000 | £1,800-£2,800 | Replace rear main seal, drop transmission, inspect flywheel | If seal has failed but no bottom-end damage | 1 - 2 days |
Full Replacement - Rebuilt M177 engine with upgraded components Best Value | £12,000-£18,000 | £8,500-£14,000 | Supply & fit rebuilt M177 engine with upgraded oil separator, new rear main seal, full gasket set | If oil loss has caused bearing or bottom-end damage | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical 2017-2022 GLC63 AMG 4MATIC+ is worth approximately £35,000-£60,000 depending on mileage and condition. The GLC63 sits firmly in the £15,000+ band - replacement cost is typically small relative to vehicle value, making a full rebuilt engine a justifiable investment for owners of these high-value performance SUVs.
Our Recommendation
Our Recommendation
The oil separator is the root cause of most M177 rear main seal leaks. If you notice oil around the transmission bellhousing or a burning oil smell, have the crankcase pressure checked immediately. A simple test - attempting to remove the oil fill cap at idle - can reveal excessive vacuum (cap difficult to remove) or excessive pressure (air release). If caught early, replacing the oil separator alone (£500-£800 at a specialist) prevents the much more expensive rear main seal replacement. If the rear main seal has already failed, replacing both the seal and the oil separator together is the only sensible approach. On a GLC63 worth £35,000-£60,000, the full rebuilt engine route is justifiable if bottom-end damage has occurred.
Don't Let Oil Separator Failure, Rear Main Seal Leaks, or Turbocharger Issues Write Off Your Mercedes GLC63
Whether you're facing M177 oil separator failure on your V8 GLC63 or considering the long-term reliability of the new M139l PHEV, 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 hand-built V8 engines inside out.
Compare rebuilt M177 Mercedes GLC63 engine prices
12-Month Minimum
UK Specialists Vetted
Best Price GuidanceImportant Information
Important Information
"All prices are indicative UK market ranges based on historical quote data and repair requests from our network of engine specialists. Dealer pricing is estimated based on published main dealer labour rates and genuine OEM parts pricing. Specialist pricing reflects actual quote data from EnginesMarket's UK network. Actual costs vary depending on damage severity, vehicle condition, variant, and workshop location within the UK. Use our free comparison tool to get tailored quotes for your specific Mercedes GLC Class GLC63. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier."
Mercedes Benz GLC Class GLC63 Engine ReplacementFrequently Asked Questions
Question 1How much does a Mercedes GLC63 AMG engine replacement cost in the UK-
Short summary: A rebuilt M177 V8 engine for the GLC63 costs £7,000-£14,000 supply-only; a rebuilt M139l PHEV four-cylinder costs £9,000-£15,000 supply-only. Fitting adds £1,500-£2,500 depending on complexity - AMG V8 and PHEV work requires specialist knowledge.
- GLC63 V8 (M177.980): rebuilt unit £7,000-£14,000; used engine from £4,000
- GLC63 S E Performance (M139l PHEV): rebuilt unit £9,000-£15,000; used from £5,000
- Oil separator replacement (labour only): £500-£800 at specialist
- Rear main seal replacement (labour only): £1,800-£2,800 at specialist
Question 2What are the signs of oil separator failure on a Mercedes GLC63-
Short summary: The most common sign is a burning oil smell or oil dripping from the rear of the engine. A simple test - attempting to remove the oil fill cap at idle - can reveal excessive vacuum (cap difficult to remove) or excessive pressure (air release). If ignored, oil separator failure leads to rear main seal leaks and potential engine damage.
- Oil around the transmission bellhousing - classic sign of rear main seal leak
- Burning oil smell from the engine bay
- Whistling or howling sound from the engine at idle
- Oil fill cap difficult to remove at idle (excessive vacuum)
- If caught early, oil separator replacement costs £500-£800
Question 3Is the Mercedes GLC63 V8 engine reliable-
Short summary: The M177 is a fundamentally strong hand-built AMG V8 - one of Mercedes' most impressive modern engines. It has a small number of well-documented weak points (oil separator, rear main seal, turbochargers) that are well understood by specialists. With proper maintenance, the M177 routinely exceeds 100,000 miles.
- M177 is a hand-built AMG masterpiece - strong and characterful
- Oil separator and rear main seal issues are the most frequent problems
- Regular oil changes (every 10,000 miles) are essential - use MB 229.5 spec oil
- Many M177 engines exceed 100,000 miles with proper maintenance
Question 4How long does a Mercedes GLC63 engine last-
Short summary: Properly maintained M177 V8 engines routinely reach 100,000-150,000 miles before major work. The M139l PHEV four-cylinder is too new for definitive long-term data - reliability is unproven as of 2026.
- M177 (2017-2022): 100,000-150,000 miles with regular servicing
- M139l PHEV (2024-present): too early for definitive data - reliability unproven
- Service interval is 10,000 miles or 12 months - use Mercedes-spec oil only
- Late oil changes accelerate oil separator failure and turbocharger wear
Question 5Is it worth replacing the engine in my Mercedes GLC63-
Short summary: Yes, if the GLC63 is otherwise in good condition with no rust or major electrical faults. A rebuilt M177 costs £7,000-£14,000 - far less than replacing a £35,000-£60,000 vehicle. The GLC63's strong residual values make engine replacement financially justifiable.
- GLC63 values: £35,000-£60,000 depending on year, mileage and condition
- Rebuilt engine with upgraded components fixes original weak points
- Supply & fit typically £9,000-£17,000 depending on engine code
- New engine includes 12-month unlimited mileage warranty
Question 6What's the difference between the V8 GLC63 and the new PHEV GLC63-
Short summary: The 2017-2022 GLC63 uses the M177 4.0L twin-turbo V8 (476-510hp) with a characterful AMG soundtrack. The 2024-present GLC63 S E Performance uses the M139l 2.0L four-cylinder with plug-in hybrid (671hp) - more power, but a very different character. The V8 has been discontinued; the new model is a completely different car.
- V8: 4.0L, 476-510hp, hand-built, characterful V8 sound, proven reliability
- PHEV four-cylinder: 2.0L, 671hp, electric turbocharger, plug-in hybrid
- V8 discontinued after 2022; PHEV launched 2024
- Enthusiast feedback on the four-cylinder is mixed - it's quicker but lacks V8 character
Why Choose UsCompare Mercedes GLC Class GLC63Engine PricesToday
100+ AMG V8 engines supplied through our network
12-Month Warranty on every rebuilt GLC63 engine
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supply & fit available for V8 and PHEV
Comparing quotes for your Mercedes GLC63 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 M177 V8 and M139l PHEV inside out. Whether you need a used engine, a reconditioned unit, or a full rebuilt engine with upgraded oil separator and rear main seal components, we'll connect you with the right specialist for your exact GLC63 - with a minimum 12-month warranty on every engine supplied.
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