How much does a Mercedes SLK R171 engine replacement cost in the UK?

A reconditioned R171 engine typically costs £1,800–£9,000 supply only [MB-QUOTE], depending on engine — the volume SLK 200 Kompressor sits at £1,800–£3,500. Fitting adds 10–18 hours labour at specialist rates due to the roadster‑specific engine bay packaging. Use our calculator for a personalised figure.

Which Mercedes R171 engine is the most reliable?

The M113.989 (SLK 55 AMG) — a 5.4‑litre V8 with 360 bhp and legendary M113 durability. The only common issue is the crank position sensor failing at around 10 years old — a £300–£500 fix. For non‑AMG buyers, the M272.969 (SLK 350 facelift, 2008–2011) is the most reliable V6, with the balance‑shaft issue resolved from 2008 onwards.

What are the common problems with the Mercedes SLK R171?

M271 timing chain stretch (SLK 200 Kompressor), M272 balance shaft wear (early SLK 280/350), Varioroof retractable hardtop mechanism failure, rear subframe rust, and — AMG‑specific — crank position sensor failure on the M113 V8.

Is the Mercedes SLK R171 reliable?

It depends heavily on which engine you choose. The M113 V8 in the SLK 55 AMG is legendary for its durability. The facelift M272 V6 (2008–2011) is reliable. The M271 four‑cylinder has timing chain issues — avoid pre‑2007 cars unless chain history is documented. The biggest reliability challenge is the Varioroof mechanism and rear subframe rust — inspect both thoroughly before purchase.

Which Mercedes R171 engine should I avoid?

No engine outright — but a pre‑2007 M271 (SLK 200 Kompressor) without documented timing chain replacement is the one we'd approach cautiously, given the £1,200–£2,500 repair cost. An early M272 (SLK 280/350, pre‑2006) without balance‑shaft history is the second — check the engine number against the affected range.

How do I know if my R171 engine needs replacing?

Cold‑start rattle (M271 timing chain or M272 balance shaft), engine management light, rough running or misfire, or — on the M113 AMG — intermittent stalling (crank position sensor). Use our diagnostic calculator for a personalised assessment.

Is it worth replacing a Mercedes SLK R171 engine, or should I scrap the car?

Depends on the car's value and roof condition. Against a well‑kept £6,000 R171, a £2,000–£3,500 M271 recon is 33–58% of the car's value — safe. Against a tired £3,500 example, the same recon is 57–100% — walk away. Our 70% Mercedes threshold is the line. If the Varioroof mechanism needs replacing at the same time, evaluate carefully.

How long do Mercedes R171 engines last?

The M113 V8 can exceed 200,000 miles with proper servicing. The M272 V6 can reach 150,000+ miles with balance‑shaft maintenance on early cars. The M271 four‑cylinder is the most fragile — 100,000–150,000 miles is achievable with proactive timing chain replacement at 60,000–80,000 miles.

What is the difference between the R171 and the R172 SLK?

The R171 is the second‑generation SLK (2004–2011, this page), while the R172 is the third generation (2011–2016), later renamed SLC. The R172 has updated styling, more powerful engines, and improved technology. The R171 is lighter and more classic in its roadster feel.

How do I find my Mercedes R171 engine code?

Listed on the VIN plate (visible through the windscreen) and vehicle documentation; also stamped on the engine block (visible from below). Tell us your variant and registration year (pre‑facelift 2004–2008 or facelift 2008–2011) and we'll identify it — 25+ vetted Mercedes specialists will confirm it for free.

R171 Engine Replacement Cost UK

Name: Mercedes SLK R171 UK Engine Enquiry Data 2025
Creator: MercedesEngines.uk

Mercedes SLK R171 Engine Codes — The Complete Database

Every engine fitted to the R171 specifically — from the entry‑level 1.8‑litre Kompressor to the 5.5‑litre AMG V8, plus the M272 V6 family that powered the mid‑range cars.

Engine CodeFamilyFuelDisplacementPowerYears (R171)Variants (badges)Reliability2025 EnquiriesAvg. Recon Cost

M271.944M271Petrol, supercharged1.8L (1796 cc)163 bhp (120 kW)2004–2008SLK 200 Kompressor★★★☆☆ [PROVISIONAL]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M271.954M271 EVOPetrol, supercharged1.8L (1796 cc)184 bhp (135 kW)2008–2011SLK 200 Kompressor★★★½☆ [PROVISIONAL]— (pattern data)£2,000–£3,500 [MB-QUOTE]

M272.942M272Petrol, V63.0L (2996 cc)231 bhp (170 kW)2005–2011SLK 280★★★★☆ [PROVISIONAL]— (pattern data)£2,500–£4,500 [MB-QUOTE]

M272.963M272Petrol, V63.5L (3498 cc)272 bhp (200 kW)2004–2008SLK 350★★★★☆ [PROVISIONAL]— (pattern data)£2,800–£5,000 [MB-QUOTE]

M272.969M272Petrol, V63.5L (3498 cc)305 bhp (224 kW)2008–2011SLK 350★★★★☆ [PROVISIONAL]— (pattern data)£3,000–£5,500 [MB-QUOTE]

M113.989M113Petrol, V8, AMG5.4L (5439 cc)360 bhp (265 kW)2004–2011SLK 55 AMG★★★★½ [PROVISIONAL]— (pattern data)£5,000–£9,000 [MB-QUOTE]

Engine CodeFuelPowerYearsReliabilityEnquiriesAvg. Recon Cost

M271.944M271Petrol, supercharged163 bhp (120 kW)2004–2008★★★☆☆ [PROVISIONAL]— (pattern data)£1,800–£3,200 [MB-QUOTE]

M271.954M271 EVOPetrol, supercharged184 bhp (135 kW)2008–2011★★★½☆ [PROVISIONAL]— (pattern data)£2,000–£3,500 [MB-QUOTE]

M272.942M272Petrol, V6231 bhp (170 kW)2005–2011★★★★☆ [PROVISIONAL]— (pattern data)£2,500–£4,500 [MB-QUOTE]

M272.963M272Petrol, V6272 bhp (200 kW)2004–2008★★★★☆ [PROVISIONAL]— (pattern data)£2,800–£5,000 [MB-QUOTE]

M272.969M272Petrol, V6305 bhp (224 kW)2008–2011★★★★☆ [PROVISIONAL]— (pattern data)£3,000–£5,500 [MB-QUOTE]

M113.989M113Petrol, V8, AMG360 bhp (265 kW)2004–2011★★★★½ [PROVISIONAL]— (pattern data)£5,000–£9,000 [MB-QUOTE]

Overview

Mercedes SLK R171 — Overview

The R171 is the second generation of the Mercedes‑Benz SLK‑Class, produced from 2004 to 2011 as the successor to the R170.

Built on a heavily revised platform with increased use of high‑strength steel, it offered a retractable hardtop that could be opened or closed in 22 seconds. A significant 2008 facelift brought new engines — the M271 Evo with 184 bhp and the M272 3.5‑litre V6 with 305 bhp. At the top of the range sat the SLK 55 AMG — a 5.4‑litre V8‑powered roadster that could hit 62 mph in 4.9 seconds.

Key Facts

Platform

Mercedes R171

Predecessor

R170

Successor

R172 (later renamed SLC)

Sibling body styles in this generation

None (roadster only)

Market Intelligence

The R171 SLK generated an estimated 276+ UK engine enquiries in 2025 [MB-VERIFIED — PLACEHOLDER], concentrated on the SLK 200 Kompressor and SLK 350 V6 as these stylish roadsters enter affordable second‑hand ownership.

Mercedes SLK R171 — Overview

The R171 is the second generation of the Mercedes‑Benz SLK‑Class, produced from 2004 to 2011 as the successor to the R170.

Built on a heavily revised platform with increased use of high‑strength steel, it offered a retractable hardtop that could be opened or closed in 22 seconds. A significant 2008 facelift brought new engines — the M271 Evo with 184 bhp and the M272 3.5‑litre V6 with 305 bhp. At the top of the range sat the SLK 55 AMG — a 5.4‑litre V8‑powered roadster that could hit 62 mph in 4.9 seconds.

Key Facts

Platform

Mercedes R171

Predecessor

R170

Successor

R172 (later renamed SLC)

Sibling body styles in this generation

None (roadster only)

Market Intelligence

The R171 SLK generated an estimated 276+ UK engine enquiries in 2025 [MB-VERIFIED — PLACEHOLDER], concentrated on the SLK 200 Kompressor and SLK 350 V6 as these stylish roadsters enter affordable second‑hand ownership.

Best & Worst Engines

Best Petrol Overall

M113.989 (SLK 55 AMG)

“The 5.4‑litre naturally aspirated V8 — 360 bhp, 510 Nm of torque, and the most reliable engine in the R171 range. The M113 is legendary for its durability — the only real issue is the crank position sensor failing at around 10 years old. It's the engine that makes the SLK 55 AMG a future classic.”

Who it's for: enthusiasts who want V8 power and proven reliability — and understand that V8 running costs come with the territory.

Highest Risk

M271.944 (SLK 200 Kompressor, pre‑facelift)

“The 1.8‑litre supercharged four‑cylinder — 163 bhp, 240 Nm of torque. The M271's timing chain is a well‑documented weak point, particularly on pre‑2007 cars. Cold‑start rattle is the warning; a snapped chain means a full replacement. Later Evo engines are improved but not immune.”

Who it's for: buyers on a budget who understand the M271's reputation and can verify chain history.

Most Expensive Failure

M272.963 (SLK 350, pre‑facelift)

“The early M272 V6 — balance‑shaft sprocket wear is an engine‑out job. Affected cars up to about 2006 can require £2,000–£3,000 repairs. The 3.5‑litre is the worst affected due to higher stress levels. Later cars (engine number 2729..30 468993 onwards) are improved.”

Who it's for: buyers who understand the M272's reputation and can verify the engine number or repair history.

Best Value

M271.954 (SLK 200 Kompressor, facelift)

“The 1.8‑litre Evo — 184 bhp, 250 Nm of torque, and a significant step up from the 163 bhp pre‑facelift unit. The facelift engine (2008–2011) has improved timing chain components and better fuel economy. It's the cheapest R171 to run and insure.”

Who it's for: buyers who want R171 style without the V6 running costs — but still check for chain history.

Most Overlooked

M272.942 (SLK 280)

“The 3.0‑litre V6 — 231 bhp, 300 Nm of torque. It's often overlooked in favour of the SLK 350, but it's the same robust M272 family with lower running costs. On facelift cars (2008+), the balance‑shaft issue is resolved. The best‑kept secret in the R171 range.”

Who it's for: buyers who want V6 refinement without the SLK 350's higher purchase price or insurance group.

Best Petrol Overall

M113.989 (SLK 55 AMG)

“The 5.4‑litre naturally aspirated V8 — 360 bhp, 510 Nm of torque, and the most reliable engine in the R171 range. The M113 is legendary for its durability — the only real issue is the crank position sensor failing at around 10 years old. It's the engine that makes the SLK 55 AMG a future classic.”

Who it's for: enthusiasts who want V8 power and proven reliability — and understand that V8 running costs come with the territory.

Highest Risk

M271.944 (SLK 200 Kompressor, pre‑facelift)

“The 1.8‑litre supercharged four‑cylinder — 163 bhp, 240 Nm of torque. The M271's timing chain is a well‑documented weak point, particularly on pre‑2007 cars. Cold‑start rattle is the warning; a snapped chain means a full replacement. Later Evo engines are improved but not immune.”

Who it's for: buyers on a budget who understand the M271's reputation and can verify chain history.

Most Expensive Failure

M272.963 (SLK 350, pre‑facelift)

“The early M272 V6 — balance‑shaft sprocket wear is an engine‑out job. Affected cars up to about 2006 can require £2,000–£3,000 repairs. The 3.5‑litre is the worst affected due to higher stress levels. Later cars (engine number 2729..30 468993 onwards) are improved.”

Who it's for: buyers who understand the M272's reputation and can verify the engine number or repair history.

Best Value

M271.954 (SLK 200 Kompressor, facelift)

“The 1.8‑litre Evo — 184 bhp, 250 Nm of torque, and a significant step up from the 163 bhp pre‑facelift unit. The facelift engine (2008–2011) has improved timing chain components and better fuel economy. It's the cheapest R171 to run and insure.”

Who it's for: buyers who want R171 style without the V6 running costs — but still check for chain history.

Most Overlooked

M272.942 (SLK 280)

“The 3.0‑litre V6 — 231 bhp, 300 Nm of torque. It's often overlooked in favour of the SLK 350, but it's the same robust M272 family with lower running costs. On facelift cars (2008+), the balance‑shaft issue is resolved. The best‑kept secret in the R171 range.”

Who it's for: buyers who want V6 refinement without the SLK 350's higher purchase price or insurance group.

Mercedes SLK R171 — Ownership Economics

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

M271.944 (SLK 200 Kompressor, pre‑facelift)60k–120kTiming chain stretch£1,200–£2,500£1,800–£3,200

Watch — chain issues well‑documented

M271.954 (SLK 200 Kompressor, facelift)60k–120kTiming chain stretch£1,200–£2,500£2,000–£3,500

Best Value — improved but not immune

M272.942 (SLK 280)60k–120kBalance shaft wear (early)£2,000–£3,000£2,500–£4,500

Overlooked Gem — V6 refinement

M272.963 (SLK 350, pre‑facelift)60k–120kBalance shaft wear£2,000–£3,000£2,800–£5,000

Watch — early cars at risk

M272.969 (SLK 350, facelift)60k–120kBalance shaft wear (rare)£2,000–£3,000£3,000–£5,500

Best V6 — improved engine

M113.989 (SLK 55 AMG)60k–120kCrank position sensor£300–£500£5,000–£9,000

Best Petrol — legendary V8 reliability

EngineTypical MileageCommon Major FailureRepair Cost (Specialist)Replacement Cost (Recon)Ownership Verdict

M271.944 (SLK 200 Kompressor, pre‑facelift)60k–120kTiming chain stretch£1,200–£2,500£1,800–£3,200

Watch — chain issues well‑documented

M271.954 (SLK 200 Kompressor, facelift)60k–120kTiming chain stretch£1,200–£2,500£2,000–£3,500

Best Value — improved but not immune

M272.942 (SLK 280)60k–120kBalance shaft wear (early)£2,000–£3,000£2,500–£4,500

Overlooked Gem — V6 refinement

M272.963 (SLK 350, pre‑facelift)60k–120kBalance shaft wear£2,000–£3,000£2,800–£5,000

Watch — early cars at risk

M272.969 (SLK 350, facelift)60k–120kBalance shaft wear (rare)£2,000–£3,000£3,000–£5,500

Best V6 — improved engine

M113.989 (SLK 55 AMG)60k–120kCrank position sensor£300–£500£5,000–£9,000

Best Petrol — legendary V8 reliability

The R171 rule

A £2,000–£3,500 M271 recon against a £3,000–£8,000 R171 sits at 25–117% of the car's value. On a sub‑£3,500 R171, that brushes our 70% Mercedes threshold — we'll honestly tell you to walk away. Against a well‑kept £6,000+ example, the same recon drops to a routine 33–58% — a repair decision, not a financial one. Value the car first, and always budget for the Varioroof mechanism — the biggest non‑engine cost on this generation.

Key Takeaways

Which R171 Costs Least To Own?
SLK 200 Kompressor (M271) — cheapest to run, insure and maintain, but watch for chain history.
Which R171 Costs Most To Own?
SLK 55 AMG (M113) — V8 running costs, AMG parts prices, 16‑spark‑plug changes.
Which R171 Is Best Value?
SLK 280 (M272) — V6 refinement, lower running costs than the SLK 350, and the most overlooked engine in the range.

Common Problems

01

M271

Timing Chain Stretch (SLK 200 Kompressor)

Affected models:

Typical failure mileage:

Root cause:

Tiered Cost Table

Our Recommendation

On any M271 R171, listen for cold‑start rattle — a £1,200–£2,500 chain replacement is far cheaper than the £1,800–£3,200 engine replacement that follows if the chain snaps. Facelift cars (2008+) are improved but not immune.

02

M272

Balance Shaft Wear (SLK 280 / SLK 350)

Affected models:

Typical failure mileage:

Root cause:

Tiered Cost Table

Our Recommendation

On any M272 R171, check the engine number against the affected range — early units are at risk. £2,000–£3,000 now is far cheaper than the £2,800–£5,000 replacement that follows a failure. Facelift cars (2008+) are significantly improved.

03

R171

Varioroof Mechanism Failure

Affected models:

Typical failure mileage:

Root cause:

Tiered Cost Table

Our Recommendation

Test the roof mechanism thoroughly before buying any R171 — a £500–£1,000 preventative service is far cheaper than the £1,500–£3,000 replacement that follows a complete failure. This is the biggest non‑engine cost on the R171.

04

R171

Rear Subframe Rust

Affected models:

Typical failure mileage:

Root cause:

Tiered Cost Table

Our Recommendation

Inspect the rear subframe carefully before purchase — £400–£800 now is far cheaper than the £1,500–£2,500 repair that follows if corrosion spreads. Mercedes may offer goodwill replacement, but this is not guaranteed.

R171 Engine Replacement Costs — By Engine and Condition

VariantEngine CodeUsed (Supply)Reconditioned (Supply)Rebuilt (Supply)Labour Hours

SLK 200 Kompressor (pre‑facelift)M271.944£900–£1,800£1,800–£3,200£2,800–£4,50010–14 hrs

SLK 200 Kompressor (facelift)M271.954£1,000–£2,000£2,000–£3,500£3,000–£5,00010–14 hrs

SLK 280M272.942£1,500–£2,800£2,500–£4,500£4,000–£6,50012–16 hrs

SLK 350 (pre‑facelift)M272.963£1,800–£3,200£2,800–£5,000£4,500–£7,00012–16 hrs

SLK 350 (facelift)M272.969£2,000–£3,500£3,000–£5,500£5,000–£8,00012–16 hrs

SLK 55 AMGM113.989£3,000–£5,500£5,000–£9,000£8,000–£13,00014–18 hrs

No Generation variance from the Engine Page baseline — no Engine Page exists yet for any M271, M272 or M113 family. These costs are derived from the EM_Proprietary_Data Table A — Engine Replacement Economics for comparable engines, adjusted for the R171's roadster‑class labour access and marked [MB-QUOTE] accordingly. All figures are provisional pending dedicated Engine Pages.

Core Variants

Petrol Variants

SLK 200 KompressorSLK 280SLK 350SLK 55 AMG

Scope note: All variants listed are R171 two‑door roadster only. The R171 was not available with diesel engines — only petrol four‑cylinder, V6 and V8 options were offered. The successor R172 was later renamed SLC.

Core Variants

Petrol Variants

SLK 200 KompressorSLK 280SLK 350SLK 55 AMG

Scope note: All variants listed are R171 two‑door roadster only. The R171 was not available with diesel engines — only petrol four‑cylinder, V6 and V8 options were offered. The successor R172 was later renamed SLC.

Market Intelligence

Most Requested E90 Engines (2025)

1.1. M271.954 (SLK 200 Kompressor facelift)
2.2. M272.969 (SLK 350 facelift)
3.3. M271.944 (SLK 200 Kompressor pre‑facelift)

Most Requested E90 Variants

1.1. SLK 200 Kompressor
2.2. SLK 350
3.3. SLK 280

Average E90 Replacement Cost

£2,800–£5,000 reconditioned, supply only [MB-QUOTE]

Most Common E90 Failures

1.1. M271 timing chain stretch
2.2. M272 balance shaft wear (early cars)
3.3. Varioroof mechanism failure

Live Feed

VehicleLocationIssueEnquiries

Mercedes SLK 200 Kompressor R171 (M271)

Birmingham

Cold‑start rattle / timing chain

5

enquiries

Mercedes SLK 350 R171 (M272)

London

Rattling on start‑up / balance shaft

4

enquiries

Mercedes SLK 55 AMG R171 (M113)

Manchester

Crank sensor failure / intermittent stall

2

enquiries

Updated Monthly

FAQ

BMW 3 Series E90 rear three-quarter view

Why UK Mercedes SLK R171 Owners Trust MercedesEngines.uk

Trusted R171 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real R171 owners, as part of the Engine Finders network.
Compare R171 Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit.
UK Engine Replacement Services for R171
covering every variant from SLK 200 Kompressor to SLK 55 AMG, with supply‑only or full supply & fit available nationwide.

Find the best Mercedes SLK R171 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare Mercedes SLK R171 Engine Prices on EnginesMarket

Why UK Mercedes SLK R171 Owners Trust MercedesEngines.uk

Trusted R171 Engine Suppliers
every garage and engine rebuilder in our network is vetted, rated and reviewed by real R171 owners, as part of the Engine Finders network.
Compare R171 Engine Replacement Companies
see prices, warranty terms and supply & fit options side‑by‑side before you commit.
UK Engine Replacement Services for R171
covering every variant from SLK 200 Kompressor to SLK 55 AMG, with supply‑only or full supply & fit available nationwide.

Find the best Mercedes SLK R171 engine replacement UK drivers rely on. Compare real prices from trusted specialists on EnginesMarket today and get back on the road with confidence.

Compare Mercedes SLK R171 Engine Prices on EnginesMarket

Mercedes SLK R171 Engines — The Complete UK Guide

Mercedes SLK R171 Engine Codes — The Complete Database

Mercedes SLK R171 — Overview

Mercedes SLK R171 — Overview

Best & Worst Engines

Mercedes SLK R171 — Ownership Economics

Common Problems

R171 Engine Replacement Costs — By Engine and Condition

Core Variants

Core Variants

Market Intelligence

FAQ

Why UK Mercedes SLK R171 Owners Trust MercedesEngines.uk

Why UK Mercedes SLK R171 Owners Trust MercedesEngines.uk