You Can Buy A V8-Powered Mercedes-Benz SLK 55 AMG For The Price Of A Honda Civic

I have a 2009 SLK55. Ask me anything. It’s sitting next to its opposite ; an ML63.

Issues so far ;

1. leaking valve covers. For some reason they leak and will leak again after some years. And easy and safe fix, just odd
2. the Rear Main Crankshaft Seal can and probably will leak. It is a ‘transmission-out’ job but you can also decide to just let it drop a few drops of oil every week. The seal itself is just a few dozen dollars, the man hours aren’t
3. This is a 3 valve direct injection engine. The pistons foul up. I just let them clean off all carbon using specific cleaning tools, costed me here $200 and most of the head of the piston looks like original
4. Electronics are early 2000s so the circuit boards might start to cause issues. Often they regulate all kind of controls. Repairs are doable, replacements are more expensive. Luckily the 55 shares nearly everything with the other SLKs in the series
5. The rear original factory shock absorbers were done, I replaced all 4 around with an adjustable sport suspension for about $1000 and since then it drives and handles great
6. fuel economy is bad. You’ll see 11 to 20 liters per 100 km. From 20 mpg to 11 mpg if you drive fast. 20 mpg is really no problem, but then you miss out on the fun factory of the car
7. I’m 6’5 and have no problem sitting in the car. Legs, body, arms, head ; I have head room. Wearing a helmet though is difficult and will hit the roof but I’ve done quite a few laps on a track with the helmet (low profile) and it actually wasn’t a problem. If you’re 6’3 or less then you + helmet should fit in with a closed roof
8. Engine mounts ; mine weren’t good anymore. You should use original engine mounts, some after market ones were pretty bad after installation so we reverted back to original Mercedes and they are good

Changes I did which weren’t necessary to drive but made the car much more interesting than it already was:

1. installed TPMS sensors in all tires and a small display to keep track of tire pressure. You’d be surprised how much pressure drops or rises when your outside temps go up or down. I don’t know how much people are losing with under inflated tires
2. bought a real Torque Biasing Differential (Wavetrac) to replace the open diff. The open diff is safe, but on a track a LSD (or TBD in this case) keeps power to both wheels even if one is a bit slipping. Helps to accelerate better out the corners
3. Replaced transmission fluid and differential fluid even though both are technically lifetime. But a flush will also remove all small metal particles, so I think it’s smart to change those fluids once every 5 years even though they’re so called lifetime
4. There was/is a problem with a fault-code the EGR actuator/valve which doesn’t go away. We replaced the small actuator ($50) but the error sometimes shows up which makes no sense. It could be that the ECU circuit board has some connections which aren’t perfect. I expect the ECU needs to be re-soldered one day but with a local semi-DIY guy that should not be too much neither
5. Brakes ; I got both new normal brake pads for the front (OEM) and later a race set for endurance races. The latter allow for consistent safe braking on a track but aren’t suited for normal driving (they don’t work when cold and make a heck of a noise). So I replace them after each track day/weekend. It’s a job of half an hour for the fronts (only) so no big deal
6. tires ; for the track days I got a local semi-slick brand with very stiff sidewalls, great for cornering at high speed, very predictable and they keep my Continental CSC6 and Michelin PS4S tires safe
7. installed an electronic rear view mirror with camera to the front and rear (on the trunk) to both see where I am reversing into and to record anything happening on the road (dashcam). Love that.

Mine has around 120k km now, interior looks almost new except for some creases in the side bolstering of the driver seat. Exterior looks fine as well.

Driving and other comments:

1. this is like a very large go-kart with a Huge Engine. The car weighs around 1600-1700kg so it is not light, but it also not as heavy as my ML which is around 2500kg. The center of gravity of the SLK feels like about 2 inches above the road. Even a regular sedan normally doesn’t come close to the handling
2. the engine is lazy, but high on torque. From 2000 rpm it goes like a firetruck. At 5000+ it makes a heck of a noise, a good noise, European V8 noise but with American Muscle undertones. It is addictive. And is the main cause of the low MPG
3. with the hard top roof closed OR open ; it drives fine. Visibility is good, also thanks to the rear view camera
4. the trunk is small but large enough for your groceries and weekend trips with 2 people to some cottage in the mountains. If you really need to log a lot of stuff then keep the top up and you have plenty of space. If I really need more I’ll take the ML which can easily haul like 2 metric cubic meters of stuff
5. the thing is fast. not as fast as most Teslas, but those are only good in a straight line and when they turn they have serious trouble keeping up. Even with just 360 hp. And with the proper brakepads fitted the SLK can keep doing laps for half an hour without overheating ; at speed the radiator and oil cooler do a decent job. People claim 4.5s to 100km/60mph. I don’t like to do these speed tests since I like to keep the 14 year old transmission in one piece and besides that it doesn’t prove anything. So if I go fast, I do that from a rolling start, sometimes even from 2nd gear ; who cares is the small car does 4.5 or 4.7 or 5.0s ; either you smoke the other car or you lose plenty.
6. Porsches are sharper, Z4s are also interesting, but both do not have what the SLK has ; a serious natural aspirated V8. I don’t care if a new Porsche 718 Boxster is faster on the track ; I’m glad being able to keep up even though that car is just a couple of years old, but everyone will enjoy the nice V8 sounds, me included
7. The 7 speed automatic transmission is good but sluggish to move gears. So I normally let it shift on its own, manually shifting is possible with the Very Nice paddles on the steering wheel , but the transmission sometimes doesn’t listen and then you hit the rev limiter which isn’t cool
8. I’m helping the noise department with a muffler bypass valve (remote controlled) but the catalytic converters are both still installed. The noise is enough (though a real track made car without muffler makes 3 times as much sound – not always pleasant noise though). I am considering a small change to the exhaust (improved short headers), for a little more horsepower but the job is at least $1000 for perhaps as little as 10whp gain. With long tube headers you could get close to 400hp (crank) but then go as low as 4s to 100/60mph. But not legal in most countries
9. There is a bit of a downside for the more playful drivers ; the car cannot turn off its ESP/traction control entirely. Probably to keep 99% of its intended driver audience safe from spinning out of control, but annoying when you WANT to drift through a corner. While the car does allow for limited drifting ; if it seems too much of wheel spin it will either cut power or start to brake individual wheels. It wasn’t a problem on the track (I wasn’t driving OVER the limit) but I’m sure it will put off anyone who has visions of drifting Supras, E30s and Mustangs. Again for normal driving AND track use I didn’t see it as a real problem. Just so you’re aware.

All in all a very pleasant car. People are surprised by it, it is small, but it is comfortable to sit in. It drives nice, but more like a race-car or go-kart than say an E-class or a BMW 5 series. I like it because this way the car communicates very well when driving. The tail is quite happy when you step a bit on the throttle, but it is easy to catch. The design of the nose and when the top is closed is absolutely not standard. You like it, maybe not love it, or you just plainly dislike it because it is so different. Personally I only had good comments on this car, but its often from people I know so they might have been just nice.

I do like the nose of the newer R172 model more, and that one can ALSO be gotten with the 5.4 V8 but only for a short time. After that the SLK changed to “SLC” and it got a 3 liter turbo as top car. The SLC looks even more modern than the R172 but the changes are more incremental, whereas the SLK55 R171 definitely looks older than the R172 with its more modern ‘big Mercedes oval radiator gap’.

Can I recommend the car? If you can pick one up for a good price ; yes. Don’t expect these cars to increase in value, perhaps after 10 years when all V8s are finally dead and buried. But I expect the world to be in a very different shape than now, with the whole EV thing going on.

The SLK55 R171 is a fun car, low on the practicality score, but fairly unique among the current range of cars on the roads. If you don’t need more than 2 seats and like V8 sounds and sometimes enjoy gokarts or even a track day then this is a solid car.

Alternatives ; Porsche Boxster (top end with 300 ish hp) / BMW Z4M

Note ; this is not an MX5/Miata with some V8. The hard-top, higher end interior, more unique exterior and the AMG V8 put it really in it’s own category.