Mercedes Benz CLK 55/63 AMG Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK Mercedes Benz CLK 55 AMG and CLK 63 AMG engine specialists. Compare prices on reconditioned, rebuilt and used M113 and M156 hand-built AMG V8 engines - supply & fit available nationwide.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £2,800 to £9,000
Used from £2,200 · Reconditioned from £3,200 · Common codes: M113.984, M156.982
From £2,200
Tested, bare/short engine
From £3,200
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 CLK 55/63 AMG Replacement Engineto Finding the Best Mercedes Benz CLK 55/63 AMG Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryMercedes CLK 55/63 AMG - Engine History & Specs at a Glance
The Mercedes CLK 55 AMG and CLK 63 AMG represent the pinnacle of CLK performance. The CLK 55 AMG arrived in 1999 with the M113 5.4-litre naturally aspirated V8 - a hand-built AMG powerhouse producing up to 367 hp. In 2006, the CLK 63 AMG replaced it with AMG's first in-house designed V8 - the M156 6.2-litre - delivering 481 hp in standard form and 507 hp in the limited-run Black Series.
Variant HistoryMercedes CLK 55/63 AMG - Engine History & Specs at a Glance
The Mercedes CLK 55 AMG and CLK 63 AMG represent the pinnacle of CLK performance. The CLK 55 AMG arrived in 1999 with the M113 5.4-litre naturally aspirated V8 - a hand-built AMG powerhouse producing up to 367 hp. In 2006, the CLK 63 AMG replaced it with AMG's first in-house designed V8 - the M156 6.2-litre - delivering 481 hp in standard form and 507 hp in the limited-run Black Series.
Mercedes CLK 55/63 AMG
Fuel TypePetrol
Engine Size Range5.4L (M113) / 6.2L (M156)
Power Output Range347-507 hp across CLK 55/63 AMG rangeEngine History Timeline
CLK 55 AMG (C208) launched with M113.984 5.4L V8 347 hp, 510 Nm - Europe-only initially
CLK 55 AMG power increased to 367 hp in C209 generation
Second-generation CLK 55 AMG (C209) launched with M113 E55 EVO 367 hp
CLK 63 AMG launched with M156.982 6.2L V8 481 hp, 630 Nm - AMG's first in-house V8
CLK 63 AMG Black Series launched with 507 hp 630 Nm, 300 km/h top speed
2009 - CLK 63 AMG available in coupé (C209) and cabriolet (A209) body styles
CLK production ends; M156 engine continues in other AMG models
Key Specs Snapshot
Fuel TypePetrolEngine Size Range5.4L (M113) / 6.2L (M156)Power Output Range347-507 hp across CLK 55/63 AMG rangeTorque Range510-630 Nm0-62 mph4.3-5.4 secondsYears Produced1999-2009Every AMG V8 engine fitted to the Mercedes CLK 55 AMG and CLK 63 AMG is covered below, with UK rebuilt pricing and known failure points.
Mercedes CLK 55/63 AMG Engine Codes - Specifications & Replacement CostMercedes CLK 55/63 AMG Engine Codes - Specifications & Replacement Cost
5.4L V8 Petrol (1999-2006)
Power Output347 hp (C208, 1999-2002) / 367 hp (C209, 2002-2006)Torque510 Nm @ 3,000-4,300 rpmDisplacement5,439 ccBore x Stroke97.0 x 92.0 mmCompression Ratio10.5:1Valve TrainSOHC, 3 valves per cylinder (2 intake, 1 exhaust), 16 sparkplugsCamshaft DriveDouble roller chainFuel SystemBosch ME engine managementYears Fitted1999-2006
Compatible Trim Levels
- CLK 55 AMG (C208)
- CLK 55 AMG (C209)
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£2,200-£3,800
Reconditioned
Addressed known issues, tested
£3,200-£5,000
Rebuilt
Full teardown, upgraded internals
£4,000-£6,000
Common Failure
The M113 V8 is widely regarded as one of Mercedes' most robust engines. However, age-related issues do arise: valve stem seals can harden and cause oil consumption, valve cover gaskets and PCV vent housings can develop oil leaks, and the crankshaft position sensor can fail causing intermittent stalling. Engine mounts wear rapidly on AMG models.
The Mercedes CLK 55 AMG and CLK 63 AMG are powered by two of AMG's most celebrated V8 engines - the M113 5.4-litre and the M156 6.2-litre. The M113 is widely regarded as one of Mercedes' most robust engines, with age-related issues like valve stem seal wear and oil leaks being the main concerns. The M156 is a modern classic - AMG's first in-house V8 - but early engines suffer from head bolt failure, valve train wear, and high oil consumption. Every rebuilt engine supplied through EnginesMarket includes upgraded components designed to address the original failure point - plus a minimum 12-month unlimited mileage warranty.
The CLK 63 AMG's Defining Weakness
Affected Vehicles
Mercedes CLK 63 AMG (M156 E62, 2006-2009)
Typical Failure Mileage
30,000-60,000 miles
Root Cause
Early M156 engines (pre-2010) have cylinder head bolts that can break at the bolt head, allowing coolant to leak into the combustion chambers. Coolant works its way up the bolt threads and causes corrosion. Symptoms include unexplained coolant loss, misfire on cold start, white smoke from the exhaust, and in severe cases, hydro-lock that bends connecting rods and writes off the engine.
Why It Happens
Early M156 engines (pre-2010) have cylinder head bolts that can break at the bolt head, allowing coolant to leak into the combustion chambers. Coolant works its way up the bolt threads and causes corrosion. Symptoms include unexplained coolant loss, misfire on cold start, white smoke from the exhaust, and in severe cases, hydro-lock that bends connecting rods and writes off the engine.
Dealer (parts + labour)
£2,500-£4,000
Specialist (parts + labour)
£1,800-£3,000
What it involves
Replace all head bolts with updated design or ARP studs, new gaskets
Suitability
30k-60k miles; prevents catastrophic failure
1 - 2 daysDealer (parts + labour)
£6,000-£8,000
Specialist (parts + labour)
£4,500-£6,500
What it involves
Replace cylinder head(s), head bolts, gaskets, valve train components
Suitability
Required if head bolt failure has caused damage
1 - 2 daysDealer (parts + labour)
£10,000-£15,000
Specialist (parts + labour)
£7,000-£11,000
What it involves
Complete replacement engine with upgraded head bolts, bench tested, 12-month warranty
Suitability
Required if hydro-lock has bent connecting rods
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 |
|---|---|---|---|---|---|
 Preventative - Head Bolt Replacement Minor | £2,500-£4,000 | £1,800-£3,000 | Replace all head bolts with updated design or ARP studs, new gaskets | 30k-60k miles; prevents catastrophic failure | 1 - 2 days |
 Major - Cylinder Head Replacement Best Value | £6,000-£8,000 | £4,500-£6,500 | Replace cylinder head(s), head bolts, gaskets, valve train components | Required if head bolt failure has caused damage | 1 - 2 days |
Full Replacement - Rebuilt Engine Best Value | £10,000-£15,000 | £7,000-£11,000 | Complete replacement engine with upgraded head bolts, bench tested, 12-month warranty | Required if hydro-lock has bent connecting rods | 1 - 2 days |
Our Recommendation
Our Recommendation
Head bolt failure is the single most significant issue affecting the M156 engine. If you own a CLK 63 AMG, preventative head bolt replacement with updated bolts or ARP studs is strongly recommended. Don't wait for symptoms - coolant loss and misfires are signs that damage has already occurred. For cars with existing engine damage, a rebuilt unit with upgraded head bolts and components is the only safe option.
Don't Let Engine Failure Write Off Your Mercedes CLK 55/63 AMG
Engine failure on a CLK 55 AMG or CLK 63 AMG doesn't have to mean the end of the car. Whether you're dealing with M156 head bolt failure, M113 valve stem seal wear, or age-related oil leaks, EnginesMarket makes it simple to compare prices from trusted UK Mercedes CLK 55/63 AMG specialists. Every rebuilt engine includes upgraded components designed to prevent the original failure from recurring, backed by a minimum 12-month unlimited mileage warranty. Compare prices today and get back on the road without the main dealer premium.
Compare rebuilt M156 Mercedes CLK 63 AMG engine prices
12-Month Minimum
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Best Price GuidanceImportant Information
Important Information
Mercedes CLK 55/63 AMG Engine ReplacementFrequently Asked Questions
Question 1How much does a Mercedes CLK 55/63 AMG engine replacement cost in the UK-
A Mercedes CLK 55 AMG or CLK 63 AMG replacement engine typically costs between £2,200 for a used M113 unit and £9,000 for a fully rebuilt M156 engine. Specialist fitting adds £800-£1,500 due to the complexity of AMG V8 systems.
- Used M113/M156 engines: £2,200-£5,500 depending on mileage and condition
- Reconditioned units: £3,200-£7,500 supply only
- Rebuilt units: £4,000-£9,000 with 12-month warranty
- Specialist fitting adds £800-£1,500; dealer labour is significantly higher
- 12-month warranty included on all rebuilt units through EnginesMarket
Question 2Is the Mercedes CLK 55 AMG or CLK 63 AMG engine reliable-
The M113 V8 in the CLK 55 AMG is widely regarded as one of Mercedes' most robust engines - virtually faultless with proper maintenance. The M156 in the CLK 63 AMG is more complex and less reliable, with head bolt failure being the main concern.
- M113 (CLK 55 AMG): robust, reliable, age-related issues only
- M156 (CLK 63 AMG): head bolt failure risk on early engines (pre-2010)
- M156 valve train wear and high oil consumption have been reported
- Both engines can exceed 150,000-200,000 miles with proper maintenance
Question 3What is the M156 head bolt problem on the Mercedes CLK 63 AMG-
The M156 engine in the CLK 63 AMG has cylinder head bolts that can break at the bolt head, allowing coolant to leak into the combustion chambers. This is a well-known issue affecting pre-2010 M156 engines.
- Symptoms: unexplained coolant loss, misfire on cold start, white smoke
- If ignored, hydro-lock can bend connecting rods and write off the engine
- Preventative head bolt replacement costs £1,800-£3,000 at a specialist
- Early detection is critical - don't wait for symptoms
Question 4What causes oil consumption on the Mercedes CLK 55/63 AMG-
Oil consumption on AMG V8s is typically due to worn valve stem seals, which harden and crack over time, allowing oil to seep into the combustion chambers.
- Blue smoke on startup is the classic symptom
- Valve stem seal replacement costs £1,400-£3,500 depending on engine
- The M113 is otherwise bulletproof - worth fixing
- Regular oil changes every 10,000 miles are critical for longevity
Question 5How long do Mercedes CLK 55/63 AMG engines last-
Well-maintained M113 V8 engines regularly exceed 150,000-200,000 miles. M156 engines can also achieve high mileage but require preventative head bolt replacement.
- M113 (CLK 55 AMG): 150k-200k+ miles with regular servicing
- M156 (CLK 63 AMG): 100k-150k+ miles with head bolts addressed
- Regular oil changes every 10,000 miles significantly extends life
Question 6Is it worth replacing the engine in my Mercedes CLK 55/63 AMG-
On a CLK 55 AMG worth £8,000-£15,000, specialist engine replacement at £4,000-£6,000 is worthwhile if the body and interior are in excellent condition. On a CLK 63 AMG worth £25,000-£40,000+, engine replacement is almost always justifiable.
- CLK 55/63 AMG values are rising - they are future classics
- A clean, well-maintained AMG is worth saving
- Rebuilt M113/M156 engines cost £4,000-£9,000 supply only
- Compare against £10,000-£15,000 main dealer new engine quotes
Question 7Mercedes CLK 55 AMG vs CLK 63 AMG - which engine is more reliable-
The M113 in the CLK 55 AMG is significantly more reliable than the M156 in the CLK 63 AMG. The M113 is virtually faultless with proper maintenance, while the M156 has well-documented head bolt and valve train issues.
- M113 (CLK 55 AMG): robust, reliable, simpler SOHC design
- M156 (CLK 63 AMG): more powerful and rev-happy but less reliable
- The M113 is generally the more desirable engine for reliability
- The M156 is the more desirable engine for performance and sound
Why Choose UsCompare Mercedes CLK 55/63 AMGEngine PricesToday
150+ CLK 55/63 AMG engines supplied through our network
12-Month Warranty on every rebuilt CLK 55/63 AMG engine
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Comparing quotes for your Mercedes CLK 55 AMG or CLK 63 AMG engine replacement is free, quick and carries no obligation. Enter your registration above to get matched with vetted UK specialists who stock the exact M113 or M156 engine for your AMG - whether you need a used unit, a reconditioned engine or a fully rebuilt motor with a 12-month warranty and upgraded components designed to prevent head bolt or valve train failure. Get back on the road with confidence, without the main dealer premium.
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