Mercedes-Benz SLK R171

SLK in brief

The SLK was produced in three generations: R170 (1996–2004), R171 (2004–2011), and R172 (2011–2016). In 2016, the updated R172 was renamed SLC and produced until 2020. All generations feature a retractable metal Vario roof that stows away in the boot.

The SLK appeals to those who value comfort over pure sportiness: it's softer and more refined than many rivals, and with the roof up, it's suitable for driving in colder months. Downsides include just two seats and a small boot, especially with the roof down.

R171 vs R172

The R171 generation (2004–2011) received an SLR-style front end, a much sturdier body, and a more modern interior than the R170. It popularised the AIRSCARF system, which blows warm air onto the neck area, making open-top driving possible on cooler evenings. It's a cheaper way to get an SLK, but most cars are now over 15 years old.

The R172 generation (2011–2016) is larger, quieter, and better equipped. It offers more safety systems, modern turbocharged engines, and as an optional extra, a glass roof that can be darkened with the press of a button (Magic Sky Control). It's often the recommended choice in the used market.

The refreshed SLC (2016–2020) is essentially the same R172, just with a new front end, updated interior, and a 9-speed automatic transmission. If you're after the latest version of this model, it's worth checking out the SLC listings too.

Engines and transmissions

The R171 is most commonly the SLK 200 Kompressor with a 1.8-litre supercharged engine (around 163–184 hp). More powerful are the SLK 280 and SLK 350 with V6 engines (around 231–305 hp), while the SLK 55 AMG has around a 360 hp V8 engine.

The R172 features the SLK 200 and SLK 250 with a 1.8-litre turbo engine (around 184–204 hp), the SLK 250 CDI with a 2.1-litre diesel (around 204 hp), the SLK 350 with a 3.5-litre V6 (around 306 hp), and the SLK 55 AMG with a 5.5-litre V8 (around 421 hp).

Transmissions come in 6-speed manual or automatic. R171 four-cylinder versions usually had a 5-speed, while V6 versions and the R172 had a 7-speed 7G-Tronic automatic. The SLK 55 AMG came only with an automatic.

What to check when buying a used SLK

Test the roof a few times: it should operate smoothly, without judders or hesitation. In older models, roof hydraulic cylinder leaks and connector failures are common, so check for signs of hydraulic fluid and moisture in the boot.

The R171 generation is known for issues with the timing chain and its mechanism in 1.8-litre turbocharged and V6 engines: a cold engine shouldn't rattle after starting, and engine errors due to the position of the timing chain tensioners should raise suspicion. The weak point of early M272 V6 engines (around 2004–2008) is the balance shaft bearing.

The main enemy of the oldest R170 models is corrosion, especially in the areas of the wings, door sills, and boot lid. For all generations, check the service history, as convertibles often don't cover many miles, and the mileage can be inaccurate.

Versions and trims

Mercedes-Benz SLK versions are usually named after the engine, with equipment depending on the chosen packages; we list the versions most commonly found in Europe.

Comparison of R172 generation versions

For most buyers, the best choice is the SLK 200 or SLK 250 with an automatic gearbox: they're perfect for relaxed driving, and maintenance is cheaper. The SLK 350 is worth considering for its six-cylinder engine, while the SLK 55 AMG is for serious power enthusiasts.

Frequently asked questions