How much does a Mercedes SLK 55 AMG engine replacement cost in the UK?

A reconditioned M113 V8 typically costs £4,500–£7,500 supply only, with the M152 V8 higher at £6,000–£9,500. A partial M113 rebuild starts from around £8,800. Fitting adds £1,300–£2,000. Use our calculator for a figure specific to your SLK.

Is the Mercedes SLK 55 AMG engine reliable?

It depends which generation your SLK is. The R171's M113 (2005–2011) is widely regarded as one of Mercedes' most robust engines — a 3‑valve SOHC V8 that can exceed 200,000 miles. The R172's M152 (2012–2015) is more advanced but has camshaft adjuster and harmonic damper watchpoints. Check the Era Map above for your specific car.

What are the common problems with the SLK 55 AMG engine?

M113 (R171): crankshaft position sensor failure (hot‑start issues), oil leaks (rear main seal, rocker covers), oil pump pickup O‑ring degradation. M152 (R172): camshaft adjuster failure (ticking, oil in wiring loom), harmonic damper degradation, oil leaks from magnesium breather covers.

Is it worth replacing an SLK 55 AMG engine, or should I scrap the car?

Depends on vehicle value and generation. An R171 SLK 55 AMG is a £8,000–£18,000 vehicle — a £5,000–£6,000 recon is 28–75% of the car's value. An R172 SLK 55 AMG is a £12,000–£25,000 vehicle — a £6,000–£7,500 recon is 24–63% of the car's value. Evaluate carefully based on your car's generation and condition.

How do I find my Mercedes SLK 55 AMG engine code?

Listed on the VIN plate and vehicle documentation. The SLK 55 AMG covers M113 (R171, 2005–2011) and M152 (R172, 2012–2015). Tell us your registration date and we'll confirm which one you have for free.

Can I prevent the common failures on an SLK 55 AMG?

On M113: replace the crankshaft position sensor preventatively at 80,000–100,000 miles. Address oil leaks promptly. On M152: have the camshaft adjusters inspected at 40,000–60,000 miles — catching a failing adjuster early can prevent expensive wiring and engine damage. Both engines benefit from regular oil changes with Mercedes‑approved oil and shortened intervals (5,000–7,500 miles). At the first sign of hot‑start issues, ticking or oil leaks, book an inspection immediately.

Mercedes SLK 55 AMG2005–2015M113 / M152

Mercedes SLK 55 AMG Engine Replacement — Compare Prices & Get Quotes

The SLK 55 AMG is a compact V8 roadster — the R171's M113 5.4‑litre V8 and the R172's M152 5.5‑litre V8 with cylinder deactivation. Get quotes from trusted UK specialists today.

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Mercedes SLK 55 AMG Engines — from £2,500 to £10,000M113 / M152

Mercedes SLK 55 AMG Engines — from £2,500 to £10,000· M113 / M152

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The SLK 55 AMG THROUGH TIME — Era Map

Four generations. Four eras. One guide to reliability, costs and what really matters.

GenerationYearsEngine CodeReliabilityRecon CostEra Note

Why use this era map?

This table is the single source every other section on this page matches — Sections 2, 4 and 6 reference it rather than restating conflicting figures.

Real UK Cost Data

Verified Reliability

Expert Insights

Updated for 2025

Mercedes SLK 55 AMG Engine Replacement Costs

Supply Only£4,500–£8,000

Fitted (Indie)£5,800–£9,600

Warranty12–24 months

Best ForMost owners — best cost/warranty balance

Engine TypeSupply OnlyFitted (Indie)WarrantyBest For

Used Engine£2,500–£5,000£3,700–£6,5001–6 monthsBudget priority; lower‑mileage donor

Reconditioned Engine£4,500–£8,000£5,800–£9,60012–24 monthsMost owners — best cost/warranty balance

Rebuilt Engine£6,000–£10,000£7,300–£11,80012–24 monthsLong‑term ownership; 3+ year horizon

Main Dealer NewN/A — no longer availableN/AN/ANot available — reconditioned only

Figures above reflect the range across both generations; specific costs vary by era — see the Era Map above. A partial M113 rebuild starts from around £8,800. An M152 failure can be very expensive.

Labour estimate: Fitting an SLK 55 AMG engine typically takes 14–18 hours at £65–£95/hr (independent) or £110–£160/hr (London/SE dealer). V8 engines require significant disassembly.

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Common Problems

1. Crankshaft Position Sensor Failure (M113 — R171, 2005–2011)

Symptoms: Engine starts fine when cold but fails to restart when hot; intermittent stalling; engine warning light.

Typical mileage: 80,000–120,000 miles

Repair cost: £150–£400 (sensor replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: N/A — repair only

🟠 Check - book inspection if hot‑start issues occur

Our recommendation:

The crankshaft position sensor is a common failure point on the M113. Symptoms include starting fine when cold but failing to restart when hot. Mercedes specialist advice is to carry a spare in the glove box. At the first sign of hot‑start issues, have the sensor replaced — it's an inexpensive part that can leave you stranded.

1. Crankshaft Position Sensor Failure (M113 — R171, 2005–2011)

Symptoms: Engine starts fine when cold but fails to restart when hot; intermittent stalling; engine warning light.

Typical mileage: 80,000–120,000 miles

Repair cost: £150–£400 (sensor replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: N/A — repair only

🟠 Check - book inspection if hot‑start issues occur

Our recommendation:

2. Oil Leaks — Rear Main Seal & Rocker Covers (M113 — R171, 2005–2011)

Symptoms: Oil spots under the vehicle, burning oil smell, oil residue on the engine, drop in oil level.

Typical mileage: 60,000–120,000 miles

Repair cost: £400–£1,500 (gasket replacement)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: N/A — repair only

🟡 Monitor - book inspection soon

Our recommendation:

Oil leaks are common on the M113 as it ages. Rear main seal and rocker cover gaskets are the most frequent sources. If you notice oil spots or a burning smell, have the engine inspected. Replacing gaskets promptly prevents more serious damage and expensive repairs.

3. Camshaft Adjuster Failure (M152 — R172, 2012–2015)

Symptoms: Ticking noise from the engine, loss of power, rough idle, engine warning light, oil wicking into the wiring loom.

Typical mileage: 40,000–80,000 miles

Repair cost: £1,500–£4,000 (camshaft adjuster replacement and wiring repair)【PLACEHOLDER — confirm vs cost sheet】

Replacement cost: £6,000–£9,500 (full engine replacement if damage is extensive)

🔴 Immediate - if you hear ticking or see warning lights, book an inspection today

Our recommendation:

The M152's camshaft adjusters are a known weakness. They can fail, causing ticking and oil wicking into the wiring loom. If left unaddressed, this can lead to more serious engine damage. At the first sign of ticking or oil in the wiring, have the camshaft adjusters inspected immediately.

Weighing Your Options?

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SLK 55 AMG — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

SLK 55 AMG — Repair, Buy, or Replace?

Every 320d has a story. Make the right call with clear data, real-world costs, and honest guidance from UK specialists.

Can It Be Repaired?

ProblemRepairable?Typical CostWhen It Makes SenseCrankshaft sensor failure (M113)✅ Yes£150–£400Inexpensive — do preventativelyOil leaks (M113)✅ Yes£400–£1,500Routine maintenance — do preventativelyCamshaft adjuster failure (M152)✅ Yes£1,500–£4,000Catch it early — before wiring and engine damage occursHarmonic damper degradation (M152)✅ Yes£500–£1,200Replace when loose — do preventativelySevere engine damage (scoring / oil starvation)❌ Usually NoEngine replacementLittle left to salvage — replacement is the only option

Buying This SLK 55 AMG? Check These First

Buy If

R171 M113: no hot‑start issues — crankshaft sensor in good condition
R171 M113: no oil leaks — rear main seal and rocker covers dry
R172 M152: no ticking from the engine — camshaft adjusters in good condition
Full Mercedes‑AMG service history with regular oil changes

Avoid If

R171: hot‑start failure with no sensor history — crankshaft sensor may be failing
R171: oil spots under the vehicle — leaks may be significant
R172: ticking from the engine — camshaft adjusters may be failing
R172: oil in the wiring loom — camshaft adjuster failure has occurred
Poor service history — AMG V8s are sensitive to neglect

Closing Verdict

The SLK 55 AMG is a compact V8 roadster with genuine AMG character — a 5.4‑ or 5.5‑litre V8 in a small, lightweight package. The R171's M113 is widely regarded as one of Mercedes' most robust engines, with crankshaft sensor and oil leaks as the main watchpoints. The R172's M152 is more advanced, with direct injection and cylinder deactivation, but has camshaft adjuster and harmonic damper watchpoints. Buy on full service history, check for hot‑start issues (M113) and ticking from the engine (M152), and never ignore an oil leak. A well‑maintained SLK 55 AMG is a future classic; a neglected one is a £7,000+ bill waiting to happen.

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Buying Checklist

Before you buy a used Mercedes SLK 55 AMG (or before you commit to an engine replacement), check these:

Cold Start — Listen for smooth start; M113 should fire immediately, M152 should not tick

Hot Start — Check if the engine restarts when hot; crankshaft sensor indicator (M113)

Oil Leaks — Check under the car and around the engine; rear main seal and rocker covers (M113)

Tick / Rattle — Listen for ticking from the engine; camshaft adjuster indicator (M152)

Service History — including which generation (R171 or R172) and confirmed oil‑change intervals

Wiring Loom (M152) — Check for oil in the wiring loom; camshaft adjuster failure indicator

Harmonic Damper (M152) — Check for play or looseness; harmonic damper degradation indicator

MOT History — Check for emissions‑related failures

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Buy smart. Drive with confidence.

A few checks today can save thousands tomorrow. Use this checklist to avoid the most common 320d pitfalls.

Engine Codes

This table's rows match Section 1B's Era Map exactly. R171 engine code M113.989. R172 engine code M152.980.

M113 E55 (5.4 V8)

Years2005–2011

Power355–360 hp (265 kW) @ 5,750 rpm; 510 Nm @ 4,000 rpm

2025 Enquiries— (pattern data)

Avg. Recon Cost£4,500–£7,500【PLACEHOLDER】

Engine CodeYearsPower2025 EnquiriesAvg. Recon Cost

M113 E55 (5.4 V8)2005–2011355–360 hp (265 kW) @ 5,750 rpm; 510 Nm @ 4,000 rpm— (pattern data)£4,500–£7,500【PLACEHOLDER】

M152 E55 (5.5 V8)2012–2015415–422 hp (310 kW) @ 6,800 rpm; 540 Nm @ 4,500 rpm— (pattern data)£6,000–£9,500【PLACEHOLDER】

Technical Specs

M152 E55 5.5 V8, R172

Displacement5,461 cc

Cylinders8‑cylinder V‑configuration

Compression Ratio12.6:1

Fuel SystemDirect injection

ValvetrainDOHC with variable camshaft adjustment

Redline7,200 rpm

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Market Intelligence

Most Common Failure

M113: crankshaft position sensor failure / oil leaks; M152: camshaft adjuster failure【PATTERN DATA】

Average Enquiry Mileage

50,000

–70,000 miles【PATTERN DATA】

Average Replacement Cost

£5,500

–£7,500 reconditioned, supply only【PLACEHOLDER — confirm vs cost sheet】

Most Requested Engine Code

M113 (R171) — approximately 55% of SLK 55 enquiries【PATTERN DATA】

Peak Enquiry Season

Spring/Summer — roadster season【PATTERN DATA】

Regional Demand

South East18%

London16%

South West (14%)【PATTERN DATA】

Regional Demand Breakdown

18%South East

16%London

Frequently Asked Questions

All prices are indicative UK market ranges based on historical quote data from our network of engine specialists. Actual costs vary by variant, engine code, damage severity and workshop location. Use our free comparison tool to get tailored quotes. Every engine supplied through EnginesMarket carries a minimum 12‑month unlimited‑mileage warranty — always confirm terms with your chosen supplier.

Find the best Mercedes SLK 55 AMG engine replacement UK drivers rely on. Compare prices from trusted specialists on EnginesMarket today and get back on the road with confidence — from £2,500 for a used unit to £10,000 for a fully rebuilt AMG V8.

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12-Month Warranty

As standard

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