IsItAGoodCar
Reliability Guide

Common Problems with the
2008 Mercedes-Benz SLK (R171)

The facelifted R171 received the improved M273 V6 engine which resolved the balance shaft issue, plus updated styling and interior trim. The Vario-roof remained complex but was more reliable than earlier units. Rear subframe corrosion is a concern across all years.

What changed for 2008

  • •Facelift with M273 V6 engine
  • •Balance shaft issue resolved
  • •Updated styling
  • •Improved interior quality

Common MOT watch-outs

  • !Vario-roof hydraulic leaks persist
  • !Rear subframe corrosion
  • !General age-related electrical issues
2
Known Issues
1
Serious
1
Moderate
0
Minor

The 2008 period has 2 more issues than the Mercedes-Benz SLK (R171) average across all year periods.

All Known Issues

M272 V6 Balance Shaft Wear

SeriousEngine

Early 3.0L and 3.5L V6 engines used soft metal gears on the balance shaft. The gears wear down, altering engine timing and requiring a massive engine-out repair.

Most affected: SLK 280, SLK 350 (Pre-facelift)

Estimated cost: £2,500–£4,000Affects: 2004–2008

Typical symptoms

  • •Engine management light (codes P0016/P0017)
  • •Rough idle
  • •Loss of power

What to inspect before you buy

  • ✓Check engine number against the known affected range
  • ✓Ask for invoice proof of balance shaft replacement

Vario-Roof Hydraulic Leaks

ModerateBodywork & Rust

The complex folding hardtop uses multiple hydraulic cylinders that can leak as the seals age.

Most affected: All models

Estimated cost: £300–£1,000Affects: 2004–2011

Typical symptoms

  • •Roof slow to open/close
  • •Hydraulic fluid dripping onto the headlining or in the boot

What to inspect before you buy

  • ✓Operate the roof and listen for struggling pump noise
  • ✓Inspect the headlining near the windscreen header for oily stains

Buying Tips for the 2008 Mercedes-Benz SLK (R171)

  • ✓M273 engine much safer than M272
  • ✓Test roof operation carefully
  • ✓Inspect rear subframe for corrosion
2005–2007 Mercedes-Benz SLK (R171)2009–2010 Mercedes-Benz SLK (R171)

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Other Mercedes-Benz SLK (R171) Year Periods

20042005–200720082009–20102011

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