Mercedes SLK (Model r170) buying a good one

Views 7 Likes Comments Comment
Like if this guide is helpful
Mercedes SLK 230 Auto
Link to an eBay page Remove
Add up to 3 more photos
Link to an eBay page
Mercedes SLK 230 Auto

Very low prices - for a reason

The original Mercedes SLK (known as the R170 model within Mercedes circles) has been around for nearly 20 years now.  When first launched, it's metal folding roof was a real novelty.  Few European cars had ever offered such a great compromise combining open air summer motoring and a winter-proof coupe.  The model was replaced with an updated version (R171) in 2004.  Many of the original R170 cars are now in the 'banger' part of the market, with prices as low as £1000 for a running MOT'd car.  A good SLK is a fantastic car at this money - able to cruise all day on the motorway as well as enjoying a sunny country road.  Expect fuel consumption from 28-35 mpg depending on engine size (2 litre, 2.3 litre or 3.2litre). All engines are fast enough for modern traffic.  Most 2 litre and all 2.3 litre cars are supercharged.  The cars are reasonably well built and the mechanical parts are generally very strong; engines are capable of 200,000 mies or more if properly maintained.  However, they do have some significant (and costly to fix) weaknesses.  Buying a bad one will be a very painful experience.
  • Electronics - these cars are packed full of electronic control units to manage almost everything, including the roof, the gearbox, brakes and traction control in addition to the 'normal' engine management system.  These systems are very susceptible to water leaks. The price of repair or replacement can easily be so high that a mechanically sound car is not worth fixing and ends up being scrapped.  In particular several electronic boxes are located in the passenger footwell.  Blocked water drains under the windscreen can cause water to leak through the heater fan and destroy the electronics in side the car.  Some parts can cost £600-800 and require help from specialist Mercedes dealers to fix as they often need to be programmed to work with the car.   It's a similar story in the boot; this is where the roof 'computer' lives and this can also get damaged by leaky water drains below the rear windscreen.  All the drains need regular cleaning to ensure that water does not leak in to the car.  Instruction for cleaning the drains are available from various SLK owner web pages.  
  • Gearbox - most SLKs have automatic gearboxes.  These are pretty tough and reliable but do require regular oil and filter changes.  There is an electronic plug connector on the gearbox which links it to the computers.  This is badly designed and gearbox oil often leaks out.  The oil travels up the wiring into the inside of the car and damages the gearbox 'computer'.  The computer is usually fixable with careful cleaning, but labour costs can be significant.  The gearbox electronic plug itself is cheap to replace with a modified version.  This should be done when the gearbox oil is changed. Currently, the whole job costs about £300 from a specialist.
  • Folding roof - the roof seems to be pretty reliable.  Many problems seem to come from lack of use, meaning that roof components seize up.  The roof uses a hydraulic pump located in the boot.  If any of the hydraulic pipes or rams develop a leak, then the fluid level can drop and cause problems, but this does not seem to be a major issue.  There is also a roof control relay in the boot, which sometimes fails and causes the hydraulic pump to burn out.  Precautionary replacement of the relay is cheap and easy.  Other faults are sometimes caused by various switches which sense when the roof is open/closed etc. They are fairly simple to fix (but may be tricky to diagnose).  Mercedes dealers and independents have a computer diagnostic system which can often tell you which component is faulty.
  • Rust - Mercedes' rust proofing seemed to take a nosedive around the time these cars were launched. Many R107s suffer from cosmetic rust in fairly obvious places - the wheel arches and wings in particular.  The paint is also soft and the long low bonnet is very prone to stone chips, which seem to rust badly.  
  • Interiors - There are some truly vile interior colour schemes.  Most trim parts are black, but some cars had seats and dashboards in red, blue, or cream.  The trim colour is painted on.  It's a kind of latex finish and is not very durable, which means that these brightly coloured interiors can look very scruffy with scratches on the dash and centre console.  DIY repair is fairly cheap.  Black interiors with black leather seats still suffer from scratches but the wear is nowhere near as noticeable.
  • Avoiding problem cars - Do all the usual checks on a test drive - make sure that everything works.  In particular, operate the roof a couple of times. Probably best to avoid anything that actually smells damp given the electrical problems this can cause.  Buy a car with service history if possible.  If the gearbox oil has not been changed in the recent past, budget to get this done as soon as you buy.  If the seller agrees, it may also be worth asking a Mercedes specialist to connect their computer to the car and read off any fault codes in the car's memory as this will highlight many pending or current problems.
  • Buy a good one and you'll have a fantastic car for your money!  Good luck!
Have something to share, create your own guide... Write a guide
Explore more guides