Mercedes Benz SLK Class 55 AMG Engine ReplacementCompare Prices & Get Quotes
Get quotes today from trusted UK Mercedes Benz SLK Class 55 AMG engine specialists. Compare prices on reconditioned, rebuilt and used engines for the hand-built 5.4-litre and 5.5-litre naturally aspirated V8s - supply & fit available nationwide.
Supply & Fit Available
12-Month Warranty
Nationwide Delivery
100+ Suppliers
From £4,500 to £8,500
Used from £2,000 · Reconditioned from £4,500 · Common codes: M113.981, M152.980, M113.989
From £2,000
Tested, bare/short engine
From £4,500
Rod bearings addressed, tested
From quote
Upgraded bearings, full teardown, revised valvetrain
Secure enquiry - no spam, no pressure. Genuine quotes only from vetted UK Mercedes SLK Class 55 AMG specialists.
3 Simple Steps3 Simple Stepsto Finding the Best Mercedes Benz SLK Class 55 AMG Replacement Engineto Finding the Best Mercedes Benz SLK Class 55 AMG Replacement Engine
Most replacements completed within 3-5 days.
Variant HistoryMercedes Benz SLK 55 AMG - Engine History & Specs at a Glance
The SLK 55 AMG represents the pinnacle of Mercedes' compact roadster line - the only V8-powered SLK ever produced. The R171 SLK 55 AMG launched in 2004 with the M113 5.4-litre naturally aspirated V8, producing 360hp and 510Nm of torque [8†L6-L7]. This hand-built engine from Affalterbach defined the AMG brand before the turbocharging era [8†L6-L7]. In 2012, the R172 SLK 55 AMG introduced the M152 5.5-litre naturally aspirated V8, delivering 422hp and 540Nm [3†L8][3†L15-L18]. Both engines represent the last of the naturally aspirated AMG V8s in the SLK lineage.
Variant HistoryMercedes Benz SLK 55 AMG - Engine History & Specs at a Glance
The SLK 55 AMG represents the pinnacle of Mercedes' compact roadster line - the only V8-powered SLK ever produced. The R171 SLK 55 AMG launched in 2004 with the M113 5.4-litre naturally aspirated V8, producing 360hp and 510Nm of torque [8†L6-L7]. This hand-built engine from Affalterbach defined the AMG brand before the turbocharging era [8†L6-L7]. In 2012, the R172 SLK 55 AMG introduced the M152 5.5-litre naturally aspirated V8, delivering 422hp and 540Nm [3†L8][3†L15-L18]. Both engines represent the last of the naturally aspirated AMG V8s in the SLK lineage.
Mercedes Benz SLK 55 AMG
Fuel TypePetrol (naturally aspirated V8)
Engine Size Range5.4L-5.5L (M113: 5,439cc; M152: 5,461cc)
Power Output Range360-422hp across the variant's historyEngine History Timeline
M113.981 5.4L naturally aspirated V8, 360hp @ 5,750rpm, 510Nm torque (SLK 55 AMG, R171 launch)
2008 - M113.981 continues with minor refinements
M152.980 5.5L naturally aspirated V8, 422hp @ 6,800rpm, 540Nm torque (SLK 55 AMG, R172 launch)
2015 - M152.980 continues through end of R172 production
Key Specs Snapshot
Fuel TypePetrol (naturally aspirated V8)Engine Size Range5.4L-5.5L (M113: 5,439cc; M152: 5,461cc)Power Output Range360-422hp across the variant's historyYears Produced2004-2015Every engine fitted to the Mercedes Benz SLK Class 55 AMG is covered below, with UK rebuilt pricing and known failure points - from M113 oil leaks and crank sensor failure to M152 camshaft follower wear and rocker arm issues.
Mercedes Benz SLK 55 AMG Engine Codes - Specifications & Replacement CostMercedes Benz SLK 55 AMG Engine Codes - Specifications & Replacement Cost
5.4L Naturally Aspirated V8 (2004-2008)
Power Output360 hp (265 kW) @ 5,750 rpmTorque510 Nm (375 lb-ft) @ 4,000 rpmYears Fitted2004-2008Displacement5,439 ccCylindersV8, 90° V-angle, SOHC, 24-valve (3 valves per cylinder)Engine CodeM 113 E 54 / 113.981
Compatible Trim Levels
- SLK 55 AMG
- SLK 55 AMG Performance Package (R171)
Find your exact engine code, specs and UK replacement cost guide.
Used
Tested, ready-to-fit engine
£2,000-£3,500
Reconditioned
Addressed known issues, tested
£4,500-£6,500
Rebuilt
Full teardown, upgraded internals
£5,500-£8,500
Common Failure
Oil leaks and crank sensor failure - the M113 V8 is considered one of the most reliable Mercedes engines ever produced [1†L6-L7]. However, common issues include oil leaks from valve cover gaskets and the rear main seal [1†L41-L42][12†L13]. Crankshaft position sensor failure is a well-documented issue, typically around 90,000 miles, causing hot-start failure [1†L8][1†L18]. Oil pump pickup tube O-ring failure can cause low oil pressure, especially on track-driven examples [1†L11-L14][12†L25-L29]. The M113 can also develop an oil pump "whine" on startup [12†L19-L23].
The SLK 55 AMG's M113 and M152 V8s are among AMG's most celebrated naturally aspirated engines - hand-built masterpieces from Affalterbach. The M113 is widely regarded as one of the most reliable AMG engines ever produced, with a legendary reputation for durability [1†L6-L7]. The M152 is a two-generation leap forward, offering a better soundtrack and higher redline [7†L45-L46]. However, both have well-documented weaknesses that can lead to significant repair costs. Every rebuilt engine supplied through EnginesMarket includes upgraded components addressing these original failure points, plus a minimum 12-month unlimited-mileage warranty.
The R171 SLK 55 AMG's Common Issues
Affected Vehicles
Mercedes SLK 55 AMG (M113.981, 2004-2008)
Typical Failure Mileage
60,000-120,000 miles
Root Cause
The M113 V8 is known for oil leaks from valve cover gaskets and the rear main seal [9†L36-L37]. The crankshaft position sensor is a well-documented failure point, typically around 90,000 miles, causing hot-start failure - the car will start from cold fine but won't start when hot [12†L32-L33]. Oil pump pickup tube O-ring failure can cause low oil pressure, exacerbated by high oil temperatures and track use [1†L11-L14][12†L27-L29].
Why It Happens
The M113 V8 is known for oil leaks from valve cover gaskets and the rear main seal [9†L36-L37]. The crankshaft position sensor is a well-documented failure point, typically around 90,000 miles, causing hot-start failure - the car will start from cold fine but won't start when hot [12†L32-L33]. Oil pump pickup tube O-ring failure can cause low oil pressure, exacerbated by high oil temperatures and track use [1†L11-L14][12†L27-L29].
Dealer (parts + labour)
£300-£600
Specialist (parts + labour)
£200-£400
What it involves
Replace crankshaft position sensor, clear fault codes
Suitability
If hot-start failure is the only issue
1 - 2 daysDealer (parts + labour)
£600-£1,200
Specialist (parts + labour)
£400-£800
What it involves
Replace valve cover gaskets, clean oil seepage
Suitability
If oil leaks are minor and localised
1 - 2 daysDealer (parts + labour)
£1,500-£2,500
Specialist (parts + labour)
£1,000-£1,800
What it involves
Replace rear main seal, drop transmission, inspect flywheel
Suitability
If oil leak from rear of engine is confirmed
1 - 2 daysDealer (parts + labour)
£8,000-£12,000
Specialist (parts + labour)
£5,500-£8,500
What it involves
Complete engine swap with new gaskets and seals, 12-month warranty
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 |
|---|---|---|---|---|---|
 Minor - Crank sensor replacement Minor | £300-£600 | £200-£400 | Replace crankshaft position sensor, clear fault codes | If hot-start failure is the only issue | 1 - 2 days |
 Intermediate - Valve cover gasket replacement Best Value | £600-£1,200 | £400-£800 | Replace valve cover gaskets, clean oil seepage | If oil leaks are minor and localised | 1 - 2 days |
Major - Rear main seal replacement Best Value | £1,500-£2,500 | £1,000-£1,800 | Replace rear main seal, drop transmission, inspect flywheel | If oil leak from rear of engine is confirmed | 1 - 2 days |
Full Replacement - Rebuilt M113 engine Best Value | £8,000-£12,000 | £5,500-£8,500 | Complete engine swap with new gaskets and seals, 12-month warranty | If oil loss has caused bearing or bottom-end damage | 1 - 2 days |
Vehicle Value Check
Vehicle Value Check
A typical 2004-2008 SLK 55 AMG is worth approximately £10,000-£20,000 depending on mileage and condition. These AMG roadsters retain strong values for well-maintained examples, making engine replacement a justifiable investment.
Our Recommendation
Our Recommendation
The M113's crank sensor is a known weak point - keeping a spare in the glove box is a common owner recommendation [12†L33-L35]. Oil leaks on the M113 are common with age but not usually urgent unless they are heavy. Valve cover gasket replacement at a specialist is significantly cheaper than dealer rates. If you experience hot-start failure, replace the crank sensor immediately - it's a cheap and straightforward fix that prevents being stranded.
Don't Let Oil Leaks, Crank Sensor Failure, or Valve Train Wear Write Off Your Mercedes SLK 55 AMG
Whether you're facing M113 oil leaks and crank sensor failure on your R171 SLK 55 AMG or M152 camshaft follower wear on your R172 SLK 55 AMG, 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 - new gaskets and seals, fresh crank sensors, and reinforced valve train components - 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 M113 Mercedes SLK 55 AMG 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 SLK Class 55 AMG. Every engine supplied through EnginesMarket carries a minimum 12-month unlimited mileage warranty - always confirm exact terms with your chosen supplier."
Mercedes Benz SLK 55 AMG Engine ReplacementFrequently Asked Questions
Question 1How much does a Mercedes SLK 55 AMG engine replacement cost in the UK-
Short summary: A rebuilt M113 engine for the R171 SLK 55 AMG costs £5,500-£8,500 supply-only; a rebuilt M152 engine for the R172 SLK 55 AMG costs £6,500-£10,000 supply-only. Fitting adds £1,500-£2,500 depending on complexity - AMG V8 work requires specialist knowledge.
- SLK 55 AMG (M113.981): rebuilt unit £5,500-£8,500; used engine from £2,000
- SLK 55 AMG (M152.980): rebuilt unit £6,500-£10,000; used engine from £2,500
- M113 crank sensor replacement: £200-£400 at specialist
- M113 rear main seal replacement: £1,000-£1,800 at specialist
- M152 rocker arm replacement: £1,600-£2,800 at specialist
Question 2What are the signs of crank sensor failure on a Mercedes SLK 55 AMG-
Short summary: The most common sign is hot-start failure - the car starts fine from cold but won't restart when hot. This is a well-documented issue on the M113 engine, typically occurring around 90,000 miles.
- Car starts from cold without issue
- Engine won't restart after driving when hot
- No check engine light or warning codes in some cases
- Specialist advice is to carry a spare crank sensor in the glove box
- If caught early, replacement costs £200-£400 at specialist
Question 3Is the Mercedes SLK 55 AMG V8 engine (M113/M152) reliable-
Short summary: The M113 is widely regarded as one of the most reliable Mercedes engines ever produced - "almost legendary in its reliability" [1†L6-L7]. The M152 is a two-generation leap forward, considered "mega reliable" with no systemic weak points [2†L5-L6][2†L43-L44][7†L45-L46]. Both engines are fundamentally strong when properly maintained.
- M113 is considered bulletproof - oil leaks and crank sensor are the main concerns
- M152 has no systemic weak points - valve train wear is the primary issue
- Both engines are hand-built AMG masterpieces
- Regular oil changes with Mercedes-spec oil are essential
Question 4How long do Mercedes SLK 55 AMG engines last-
Short summary: Properly maintained M113 engines routinely reach 150,000-200,000 miles before major work. One owner reported an M113 engine still running strong at 116,500 miles [9†L37-L38]. The M152 is too new for definitive long-term data but is proving reliable.
- M113 (R171 SLK 55 AMG): 150,000-200,000 miles with regular servicing
- M152 (R172 SLK 55 AMG): too early for definitive data - valve train issues from 60k-100k miles
- Crank sensor inspection recommended from 90,000 miles on M113
- Service interval is 10,000 miles or 12 months - use Mercedes-spec MB 229.5 oil
Question 5Is it worth replacing the engine in my Mercedes SLK 55 AMG-
Short summary: Yes, if the SLK is otherwise in good condition with no rust or major transmission faults. A rebuilt M113 costs £5,500-£8,500 - far less than replacing a £10,000-£30,000 vehicle. AMG values remain strong, making engine replacement a justifiable investment for well-maintained examples.
- SLK 55 AMG (R171) values: £10,000-£20,000 depending on condition
- SLK 55 AMG (R172) values: £18,000-£30,000 - AMG values remain strong
- Rebuilt engine with upgraded components fixes original weak points
- Supply & fit typically £7,000-£12,500 depending on engine code
- New engine includes 12-month unlimited mileage warranty
Question 6What oil does my Mercedes SLK 55 AMG V8 need-
Short summary: Mercedes-Benz specifies MB 229.5 high-performance oil - typically 5W-30 or 5W-40 fully synthetic. The M113 V8 requires approximately 8.5 litres; the M152 V8 requires approximately 9.5 litres.
- M113 (SLK 55 AMG): MB 229.5 5W-30 or 5W-40 - 8.5L capacity
- M152 (SLK 55 AMG): MB 229.5 5W-30 or 5W-40 - 9.5L capacity
- Never use non-approved oil - can cause timing chain and hydraulic lifter issues
- Change every 10,000 miles or 12 months - stretched intervals cause oil leaks and valve train wear
Why Choose UsCompare Mercedes SLK 55 AMGEngine PricesToday
100+ AMG V8 engines supplied through our network
12-Month Warranty on every rebuilt SLK 55 AMG engine
Nationwide UK delivery
supply & fit available for M113 and M152
Comparing quotes for your Mercedes SLK 55 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 M113 and M152 V8 engines inside out. Whether you need a used engine, a reconditioned unit, or a full rebuilt engine with upgraded gaskets, seals, and valve train components, we'll connect you with the right specialist for your exact SLK - with a minimum 12-month warranty on every engine supplied.
Enter your registration
and get matched with verified Mercedes Benz SLK Class 55 AMG specialists.