Buying used: Mercedes-Benz SLK

Buying used: Mercedes-Benz SLK
Buying used: Mercedes-Benz SLK

Style, solidity and, if you’re not careful, some rust

The Mk1 Mercedes SLK, codenamed R170 and sold from 1996 to 2004, has an electric folding roof, plenty of style and a fair bit of back lane ability, as long as you accept that a contemporary Porsche Boxster or one of the sportier BMW Z3s will be ultimately quicker along those routes.

There are so many examples on the used car market that you should be able to find a good example – but you will need to concentrate hard on separating the wheat from the chaff, because many of them are, almost literally, turning to chaff.

A bit of background. SLK means ‘Sportlich, Leicht und Kurz’, or ‘sporty, light and short’. The car was very useable and the nicely-engineered Varioroof (which should open or close in about 25 seconds) added a high degree of civility. ABS, alloys and traction control were all standard equipment, while a 2000 facelift updated the bumpers and binned the ugly old black sills in favour of body-coloured side skirts.

Most of the SLKs sold were 2.3 Kompressors, producing 190bhp up to the year 2000 and 194bhp after that. You’ll also come across some 132bhp SLK 2.0s, some 161bhp SLK 2.0 Kompressors, and some 215bhp SLK 320 V6s. You might even find a 344bhp SLK 320 AMG, which could do the 0-62mph sprint in five seconds.

The supercharged and V6 engines are meaty, which is some compensation for the slightly dumb feel of the chassis. Engines don’t matter much though if the metal surrounding them isn’t solid, and the Mk1 SLK’s fearsome reputation for disintegration should heavily influence your search. Shoddy steels used by Mercedes at the turn of the century will reveal themselves in all their crumbly glory in the wheel arches, even on otherwise immaculate cars. Unclipping the indicator lens on pre-facelift cars to examine the wings’ body attachment points is likely to be a scary experience. Rear subframes can be equally horrific, while stone chips strip away the bonnet’s flimsy protection against corrosion.

If you can track down a loved and genuinely rust-free low-mileage car, it could cost you around £8000. The high-mileage horrors begin at £1500. They might well have a full history, but most cars at this end of the price range will have fallen out of the franchised/specialist dealer network ages ago. Lurking problems can include the electronics, with water leaks into the boot causing a lot of trouble. You should also be aware of malfunctioning automatic gearboxes and ignition systems tainted by oil leaking along the wires to critical ECUs.

Expert’s view

Tony Leach is the Mercedes-Benz Club’s SLK specialist. He’s owned three SLKs: a 1996 2.3 Kompressor, a 2000 2.0 K and his current car, a ’99 2.3 K, which has benefitted from an £8000 rebuild.

“The ride is firm and you notice bumps but it’s fun to drive, even at 176,000 miles,” he says. “I love the looks of the first-generation SLK, and the electric folding roof is so convenient.

“It still looks the part. Mercedes called it a mini-SL at launch. You can get them for £800 but it’s not a car you should buy on the cheap.”

Tony ran us through some typical SLK problems. In the engine department, post-facelift cars can be afflicted by engine oil contaminating the solenoid that switches the ignition from advance to retard. Mercedes did an official fix on it. If that hasn’t happened, you have the option of replacing the solenoid. Excessive whining from the supercharger could mean that it’s broken.

Transmission-wise, the auto ’boxes are preferred to the manuals from a driving perspective but it’s important to do oil and filter changes every 35,000 miles. Oil can leak past a bushing where a cable goes into the gearbox, going on from there to find its way into the electronics.

The SLK uses C-Class suspension, which has a good reputation for toughness, but the front ball joints are known to fail.

Rust is rife in the wheel arches and where the wings meet the body. Aftermarket wings are about £200. Look into panel gaps and behind the front indicator lenses for more corrosion. Boot leaks can kibosh the central locking pump.

Indicator problems could be something as simple as a dirty bulb holder, or it could be more serious issues with the CCM (the multi-function module for the roof, wipers etc). The CCM sits in a box next to the battery, along with the engine ECU and the K40 fuse, which can generate intermittent problems through crumbling solder: these will cut out the ECU and stop the engine. If the engine light doesn’t come on when the ignition key is in position II, there may be stored fault codes that need clearing.

Seizing microswitches are common on infrequently used Vario Roofs. Regular fluid changes for the boot-sited pump are important too. If the roof is squeaky in its operation, smearing Krytox synthetic grease onto the rubber seals will almost certainly cure it.

The rubberised finish that Mercedes applied to most of the cabin plastics has a habit of falling off, particularly near the handbrake. You need to hear the air circulation flap working as the fan turns on and off.

Mercedes SLK prices

£1000-£1995: early (pre-’03) high-mile cars, usually 2.3 Ks and facelifted 2.0 Ks, plus the odd 3.2
£2000-£3495: mainly 80k-mile cars, but the odd low-miler too, often in odd colours
£3500-£3999: ’02-on cars with 50-80k mileages
£4000-£5495: late-’04 cars with high-ish (£4000) or medium (£5000) mileages
Above £5500: either the best Mk1 cars or early examples of the Mk2 (R171)

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