Buying a used Mercedes CLK (W209/C209) - 2002-2009, Buying guide with Common Issues

Frameless side windows without the B-pillars, a still fresh looking exterior, keyless entry door handles which can break and your own personal seatbelt butler which can break as well. These are the things you can't find in the 1st generation CLK which is reliability-wise not a bad car at all and you can buy one for much less than 1000 euros. Of course, the price is good, but the age and the not very good rust protection are the biggest enemies of this vehicle. On the other side, the 2nd generation CLK doesn't have big issues with the rust, it's very affordable while it still looks great even today and to top of that, it doesn't have big issues with the reliability either, if you choose the right version. The build quality of the interior is good, all the materials are really durable, so peeling plastic, forget about that. Plus, you can also find well-equipped cars which have things like the adaptive cruise control, ventilated front seats or the already mentioned keyless entry. These things are not really impressive today, but back then they were available only in the most luxurious cars. On the other side, the optional navigation system is a cutting-edge multimedia device, from the 1990s. Of course, they updated it in the facelifted models, but if you want something up to date, then you have to find an aftermarket solution. The rust protection of these cars is much better than in the predecessor, however, that doesn't mean that you should not expect rust at all, because mainly the older early production cars used on winter salty roads can have rust on the rear wheel arches, on the lower part of the doors, or sometimes on the trunk lid as well. Also, after opening the hood, you get a very good access to the fender screws. And as in the other cars, they have to be intact, if not, then the fender was removed because of a minor or a major accident, or just because of a damaged paint job. Moving on to the possible issues, there are not many actually, but if the car is equipped with electrically adjustable front seats, then check if they work properly, because in many cases, the electrically adjustable headrests won't work properly. Then the seat heating can fail, but this is nothing unusual, and a faulty seat sensor can cause the airbag warning message on the instrument cluster. Definitely check also the frameless door windows as in the other cars equipped with this feature. After opening the door, both of the side windows have to lower a little, and after closing they have to close back. In some cases, the badly aligned windows can cause excessive wind noise as well. And there are of course numerous cases when the window regulators failed completely, so try them out before buying. If the car is equipped with the keyless entry feature, then check the exterior door handles, because they can fail. It's also a good idea to check the air conditioning, all the vent and all the temperature settings, since there are numerous stepper motors under the dashboard which can cause some issues. These motors control the air flaps, but the plastic arm on them can break, and the motors themselves can fail as well. In this case, the air won't blow from all of the vents as it should, and you will also hear a ticking, clicking sound behind the dash, when you turn on the ignition. As I said, the motors with the plastic arms are under the dashboard, so to replace these parts you need to remove certain parts of the dash, or even the entire dashboard. Depends which motor you need to replace, so this is definitely not very easy to fix. And lastly, there are cases of cracked third brake light plastic cover which can let the water inside the trunk lid, and in some cases, the plastic cover can fall out completely as well. The convertible version is definitely great in the summer, but the roof itself and the roof electrohydraulic mechanism can develop some issues, which can easily ruin your summer experience. So, first thing first, you should check the hydraulic pump fluid level in the trunk. Open the trunk, remove the carpet panel on the left side, and check the fluid level, easy. If it's low, then there will be a smaller or a bigger leak somewhere in this system, which is obviously not good. The hydraulic seals are getting older, which means that after approximately 10 or 12 years, they will slowly let the fluid out, mainly in cars used in hot climate areas. So the main hydraulic pump itself can leak, and all of the hydraulic arms or cylinders in other words, can leak as well, including the front lock cylinder, which is located on the front of the roof. If the roof is not working properly, but the fluid level is ok, then you should check the microswitches which can be faulty. There are 11 or 12 of them, so it will take some time to find the victim. After this, it's time to check for water leaks in the interior, because as the roof canvas gets older, the layers under it can slowly let the water inside. Plus, the rear window can come loose as well and, again, let the water in. Replacing the canvas is not cheap, but you should expect this kind of a expense if you are buying an older convertible car. Luckily, this Mercedes doesn't have any kind of more complex hydraulic or air suspension, so there is only the conventional suspension and the factory sport suspension. As usual, check for all those clunking, knocking and creaking noises, which, as usual, indicate worn control arm bushings or sway bar links. These already mentioned parts are more often worn, so you should be prepared to replace them. The most reliable petrol engines are the V8 and V6 units with the M113 and the M112 engine codes. Then there are the newer engines with the M272 and M273 engine codes, which can have the well-known balance shaft sprocket failure, which can occur in cars made to 2007. Because of this, the timing chain can fail and possibly destroy the engine, so if you don't want to risk this, then it's a good idea to buy a car made from 2008, which will have the updated parts. The last possible problem of these newer engines is related to the intake manifold plastic outside arm and the inside plastic flaps, which can break, but you can find more information about this on my website. Then, all of the petrol engines can have often worn engine mounts, so it's good to check for excessive vibration in the interior, in the seat or on the steering wheel, but this is not the end of the world. There is also the well-known crankshaft position sensor, which can fail. In this case, it will be difficult or impossible to start the engine, but it's not an expensive part, so it's a good idea to replace it preventively. Again, not the end of the world. Lastly, there are the 4-cylinder petrol engines, which are not that bad, but there are numerous cases of prematurely worn timing chains in these engines, usually after 100 000 km. So it's a good idea to have that extra money for the repair, or you can consider replacing the chain preventively after this mileage point. This can be the end of the world. And of course, let's not forget about the AMG versions. The CLK 55 AMG has the fairly simple older V8 without the supercharger. This engine doesn't have any major problems, so there is nothing to discuss here. On the other side, the newer CLK 63 AMG has the well-known 6.3 liter V8, which can have the well-known issue with the stretched or completely broken cylinder head bolts. So it's a good idea to replace the old bolts preventively with the updated bolts. But more information about this on my website. There are no extraordinary issues with the diesel engines, just the regular problems, so check them for leaks, for smoke from the exhaust, use good quality fuel, eventually some good fuel additives, and try to find an example which is not living its last days. All the engines are equipped with timing chain, which can withstand even more than 300 000 km. Except the already mentioned petrol engines, affected with the balance shaft horror story, and the 4-cylinder petrol engines. Let's move on to the transmissions. As usual, there is nothing wrong with the manual gearbox, just pay attention to the clutch which should operate smoothly without strange sounds, slipping, or shuddering. The older 5-speed automatic transmission is not that fast as the newer 7-speed, but it's usually more reliable. Unless you buy a car made to September 2003, because in these cars there is a bigger chance that the radiator will let the coolant into the gearbox oil, which will destroy the gearbox. On the other side, this issue should be already fixed, but it's still good to consider replacing the radiator preventively on these early cars, even if it's still ok. Lastly, check the gearbox for leaks, since there is a common leak from the gearbox electrical connector. This is not very expensive to fix, but it's better to check it than to drive with a low gearbox fluid level. Then there is the newer 7-speed automatic transmission which has faster gear changes, but also in cars made to 2008, it can have more of issues with the conductor plate and with the valve body. In this case, you can experience harsh downshifts in lower gears, limp mode, or harsh shifting in general. So, check for these symptoms while driving. On the other side, from 2009 they improved this gearbox which means that with regular oil changes it should work for a long time. To summarize things up, check the radiator if you are buying a car made to 2003 with the automatic gearbox. From the petrol engines it's better to choose either the older engines, or just the newest engines from 2008. And as usual, avoid cars with any kind of performance upgrades. Plus, it's good to keep 1500 euros for the additional repairs or maintenance. But if you are buying the or the AMG version, then have at least twice as much money. And as usual, if you have personal experience with this car or more information about it, then you can write it into comments. Thanks for watching.