Mercedes-Benz · Known Issues

2009 Mercedes-Benz SLK/SLC Problems: 6 Known Issues

2009 model year · 3,070+ owner reports · Updated September 2026

According to Au7o's analysis of 3,070+ owner reports, the 2009 Mercedes-Benz SLK/SLC has 6 documented known issues, with 3 rated critical. The most serious are M271 Timing Chain Stretch and Tensioner Failure ($1,500-$3,500 repair), M272 Balance Shaft Sprocket Wear and Failure ($2,000-$5,000 repair) and 7G-Tronic (722.9) Conductor Plate / Valve Body Failure Causing Limp Mode ($500-$2,200 repair). The most commonly reported issue is M271 Timing Chain Stretch and Tensioner Failure with 1,200 owner reports. Across all issues with published estimates, repair costs range from $120 to $5,000. DIY maintenance guides at au7o.io.

Frequently Asked Questions

What are the most common Mercedes-Benz SLK/SLC problems?

According to Au7o's analysis of 3,070+ owner reports, the 2009 Mercedes-Benz SLK/SLC has 6 documented issues. The most frequently reported are: M271 Timing Chain Stretch and Tensioner Failure, M272 Balance Shaft Sprocket Wear and Failure, 7G-Tronic (722.9) Conductor Plate / Valve Body Failure Causing Limp Mode. Of these, 3 are rated critical and should be addressed promptly.

Is the Mercedes-Benz SLK/SLC reliable?

The 2009 Mercedes-Benz SLK/SLC has 6 known issues documented across 3,070+ owner reports. 3 issues are rated critical: M271 Timing Chain Stretch and Tensioner Failure and M272 Balance Shaft Sprocket Wear and Failure and 7G-Tronic (722.9) Conductor Plate / Valve Body Failure Causing Limp Mode. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Mercedes-Benz SLK/SLC problems?

Repair costs for known Mercedes-Benz SLK/SLC issues range from $0 to $5,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, M271 Timing Chain Stretch and Tensioner Failure, typically costs $1,500-$3,500 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 2005-2011 Mercedes-Benz SLK/SLC M271 Timing Chain Stretch and Tensioner Failure?

The M271 supercharged four-cylinder engine in early SLK models is prone to timing chain stretch and tensioner failure. The single-row chain stretches over time, and the hydraulic tensioner fails to take up the slack. This causes a rattling noise on startup and can lead to jumped… Repairs typically run $1,500-$3,500. Severity: high.

What is the 2005-2011 Mercedes-Benz SLK/SLC M272 Balance Shaft Sprocket Wear and Failure?

The M272 V6 engine in SLK280, SLK300, and SLK350 models suffers from the well-documented balance shaft sprocket wear issue common across all Mercedes M272-equipped vehicles. The idler gear sprocket wears prematurely due to a softer-than-specification material, producing a progres… Repairs typically run $2,000-$5,000. Severity: high.

What is the 2005-2011 Mercedes-Benz SLK/SLC 7G-Tronic (722.9) Conductor Plate / Valve Body Failure Causing Limp Mode?

The electronic conductor plate integrated into the 722.9 7-speed automatic's valve body (which houses the internal TCM, speed sensors and shift solenoids) is a widely reported failure on R171 SLKs equipped with the 7G-Tronic. As the plate's internal speed sensors and soldered joi… Repairs typically run $500-$2,200. Severity: high.

What is the 2005-2020 Mercedes-Benz SLK/SLC Vario Roof Retractable Hardtop Hydraulic Leak?

The Vario Roof retractable hardtop on both R171 and R172 SLK/SLC models develops hydraulic leaks at the cylinders, lines, and pump. The most common leak points are the roof lock cylinders and the main lift cylinders. Leaking hydraulic fluid drips into the trunk area and can damag… Repairs typically run $500-$2,500. Severity: medium.

What is the 2004-2015 Mercedes-Benz SLK/SLC M271 Camshaft Adjuster (VVT) Magnet Solenoid Failure and Oil Intrusion?

The M271 four-cylinder's camshaft adjuster magnets (variable valve timing solenoids) commonly fail or become oil-fouled on R171 SLK200 Kompressor and R172 SLK250 models. A well-documented M271 defect is engine oil wicking up the solenoid connector into the wiring harness toward t… Repairs typically run $120-$550. Severity: medium.

What is the 1998-2011 Mercedes-Benz SLK/SLC Water Leaks into Trunk and Spare-Wheel Well from Blocked Drains / Boot Seals?

SLKs (R170 and R171) frequently suffer water intrusion into the trunk and spare-wheel well. The usual culprits are clogged roof/rear-window drain tubes (which fill with leaf mulch and moss), a blocked drain under the spare well, and perished or misaligned boot seals - especially… Repairs typically run $0-$350. Severity: medium.

All 6 Known Issues

2005-2011 Mercedes-Benz SLK/SLC: M271 Timing Chain Stretch and Tensioner Failure#

2005-2011 Mercedes-Benz SLK/SLC: M272 Balance Shaft Sprocket Wear and Failure#

2004-2015 Mercedes-Benz SLK/SLC: M271 Camshaft Adjuster (VVT) Magnet Solenoid Failure and Oil Intrusion#

2005-2011 Mercedes-Benz SLK/SLC: 7G-Tronic (722.9) Conductor Plate / Valve Body Failure Causing Limp Mode#

2005-2020 Mercedes-Benz SLK/SLC: Vario Roof Retractable Hardtop Hydraulic Leak#

1998-2011 Mercedes-Benz SLK/SLC: Water Leaks into Trunk and Spare-Wheel Well from Blocked Drains / Boot Seals#

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