Some say it’s a bargain. Some say it’s a money pit. And some say it’s a nightmare which you should not purchase out of warranty. But sometimes it’s just hard to not buy a car like this – or just not to think of buying this thing.

This thing – the S class. High ranking politicians had one of these, various country leaders had one of these, dictators? Yes, they also often have one of these: very interesting

But it’s also a car which always brings new technologies to the automotive industry and it’s also a car, which should look great even after 15 or 20 years after the first model was produced. But let’s be honest, while the predecessor of this S class-the W220 had plenty of new tech, it was also spiced with bigger cost reduction measures which caused numerous reliability and rust issues + the design of this W220, say what you want, it really doesn’t aged very well. Mainly the front of the car of the before facelift versions looks really outdated at this day and age ↓ ↓ ↓

However look at the W221! The exterior of this car not only looks great even today, but it’s also more interesting than the exterior of the newest W222 S class! And the cost reduction with the new tech? Well, it seems like at this time Mercedes woke up, cut most of the cost reduction to an optimal level and fixed numerous things which were not acceptable in the predecessor. But while they fixed plenty of things they also unintentionally (or intentionally?) did a couple of bigger mistakes…

There is an awesome quote in the brochure of this car, there is something like: We give the best for people who expect the best.

Ok, but if the engine mounts made from chocolate, the balance shaft made from potatoes and the gearbox made from carrots are counting as the best, then there is a problem in the Matrix – somewhere.

But let’s not overtake the things which should not be overtaken and let me finish the damn intro with something like:

This is a VERY COMPLEX car and you have to understand that the complexity comes with risk but also with rewards. Is it ok?



The interior of this Mercedes can be equipped with almost everything you can imagine so it’s easier to mention the things it can’t have:

There is no:

  • touch screen
  • wireless phone charger
  • Bluetooth audio streaming
  • Android auto or Apple car play compatibility
  • USB port
  • heated or cooled cup holders
  • aaand I don’t know what more is missing, if you know about something else then you can write it in the comments!

But let’s be honest, most of these things are not there because of the age of the car, so that’s nothing unusual.

There is:

  • wide comfortable and supportive front electrically adjustable massage seats which do have numerous individual air cushions in them
  • heated and ventilated front and rear seats
  • night vision system
  • noise insulating infrared-reflecting double glazing
  • 2 part sunroof
  • Pre-Safe safety system-which makes crashing into stuff more comfortable
  • complex automatic AC
  • and I could continue like forever…

+ Obviously let’s not forget that the rear passengers can have almost every comfort feature in the back as well, including power sunshades in doors and on back window, fridge, separate screens with controls and so on...

Some of this stuff was optional, some of it standard on specific models.

By the way when it comes to music, there is no genuine AUX socket anywhere (but it can be retrofitted). Instead, there is only a slot for SD cards under the front AC control panel- behind a small cover.

On early cars this slot is bigger than a regular SD card, so you will need a PCMCIA adaptor → in which you can put the regular SD card → then put all this in the slot → and just then play the damn music finally. On facelifted cars on the other hand, the slot is a regular SD card slot so in this case you don’t need the adaptor.

Materials, build quality

Soft touch coating

All the used materials are high quality and pretty durable, except the soft touch coating of the buttons on the steering wheel and on the glove box opening button. On the before facelift cars this coating becomes worn and sticky and it will look horrible. But there is no need to panic, since you can remove this top sticky layer by cleaning these buttons properly. Just don’t clean them with some aggressive alcohol cleaner because you will remove the main layer too!

how to fix the sticky buttons

Loose leather

Then there are many cases of more or less loose/wrinkled leather usually on the front armrest, but occasionally also on the door panel armrest + on the before facelift cars the front driver’s seat base leather can be more often loose too (but this also depends on the drivers weight and the mileage of course).

how to fix the loose leather on armrest + how to remove it

how to fix the loose leather on seat and armrest

Build quality

The interior build quality is very good, so again a big step forward compared to the predecessor. But nothing is perfect, so numerous owners complained about creaking/squeaking or buzzing sounds from the front door panels – especially from the wood trim area. This sound can be caused by the plastic LED ambient lighting strip – behind the wood trim, which can become loose. But the sound can be caused by the door panel itself too – which is making contact with the metallic part of the door. In both cases you can put felt tape on contact points to eliminate the noises.

some more information about this door panel noise here and here

video – how to fix the door panel noise

The interior of the V12 models does have a more premium feel compared to the other standard versions. This is because all the surfaces are covered in leather instead of the standard plastic finish of the various parts – in the less equipped models.

Body, paintjob, rust protection

Luckily unlike the predecessor, this S class is not famous for rust issues. And it seems like Mercedes wanted to be really sure that it won’t rust that much, so the hood, front fenders, doors and the trunk lid are made from aluminum. And of course the rust protection of the remaining parts of the body is also very good.

However, if you are using the car on winter salty roads then it’s good to clean the rear wheel arches from inside and put some wax there – this part is from steel and is a bit more prone to rusting.

Possible problems

1. Optional front dynamic multicontour seats

I will start with the optional front dynamic multicontour seats which are like really, really complex. And the complex things can obviously break. So leaking air bladders are not uncommon, occasionally the electronic modules can be faulty-or they will only need a software update, and sometimes even the seat wiring can be damaged.

some info on how to fix seat wiring

To fix for example the leaking air bladders you either buy a complete air bladder assembly, or you can use some flexible vinyl adhesive on the leaking spots which will fix the leaks. For how long will the glue lasts? Well who knows? But you can try it. Just keep in mind that either way you will have to disassemble certain parts of the seat. If you can’t do it yourself then keep approx. 900 € which is the approximate price for replacing the seat air bladder assembly.

how to fix leaking seat air bladder video

All in all, it’s really important to check all the adjustments of these seats. Check the lumbar support, and if the car is equipped with the dynamic multicontour seats then check if all the bladders are inflating and deflating without any issues, check the massage feature and try to adjust the side bolsters. But actually the easiest is to test the bladders via the original diagnostic software (Star diagnostic program), which will tell you if the bladders are holding the air without leaks and it will show you the fault codes from these seats as well.

Obviously, the seats can be also heated and ventilated so test these features too. But focus mainly on the seat heating – it can be more often faulty, and it costs up to $1 200/seat to fix it.

The dynamic seat feature is pretty awesome since if you are cornering, then the dynamic seat will inflate the particular bolster on the seat to give you maximal support in the seat.

2. Amplifier

-There are many cases of dead amplifier = in this case there will be no sound from the multimedia system or the sound will occasionally cut off and eventually you won’t see the radio stations either.

3. AC system

-The AC system can have a couple of issues too. First of all the blower motor itself can fail completely, or occasionally it will cut off, and eventually it will just make a strange squeaking sound at low speed. The motor wears out over time and collects dirt on the brushes so this is nothing extraordinary. But luckily the motor is located in the passenger footwell area under the glove box – it’s held by 5 screws so it’s not hard to replace it. But before replacing it, first you can try to clean it with compressed air which can occasionally bring it back from the dead. But if your motor still works, then you will extend the lifetime of it by cleaning it. how to remove the blower motor video

Over time a decent amount of dirt and black carbon ash from the electronic brushes will accumulate in the motor assembly causing it to spin harder-so clean it and put some oil on the bearings of the shaft.

However sometimes the blower regulator/resistor which is next to the motor can fail, causing the motor to occasionally cut off, eventually it will not blow the air very strong-even if its adjusted to full speed + you also get a fault code for this regulator: 951D A32n1 blower regulator/resistor fault code

If your car is equipped with the 4-zone AC, then the rear blower motor regulator can fail too → causing the same issue as the front. On the other side the blower motor itself is usually ok.

After you checked the damn blower motor, you should also check the AC temperature settings, since the front heater valve which is located under the windshield wipers can fail causing only cold air to blow from the front vents.

how to replace front change over valve

how to replace the front change over valve video

But this is not the only valve which can fail, because if you have 4-zone AC then the valve which controls the rear AC temperature can fail too. However in this case the situation will be the exact opposite of the front valve failure, which means that only hot air will blow from the center rear vents even if the temperature is set to the coldest settings – In other words in summer you can set up a sauna in the rear, and if you turn off the rear AC then you can use the center console storage area as an oven since your center console becomes really hot anyway.

4. Washer fluid leaks

-Then there are more often cases of leaking windshield washer fluid, mostly because of the rubber grommets seated in the tank which will over time not seal properly, or because of a hose. Occasionally the headlight washer assembly can leak as well-in this case there will be a puddle directly below the headlights usually in cold weather + don’t forget to test the windshield washers before buying because the 2 washer motors mounted on the washer tank can break too.

detailed info on windshield washer reservoir and motor

how to remove the bumper video – to fix the leaking headlight washers

5. Sunroof motor

-This Mercedes can be equipped with the regular or with the panoramic sunroof. Either way try to open and close the sunroof a couple of times since the sunroof can get stuck because of the skipping motor. This sunroof motor will have play due to the rubber mounts on the mounting screws of this motor, so it gets loose and it will make a loud clicking/rattling skipping noise. If the gear on the motor is not worn then you can fix this issue pretty easily for free by adding washers to the mounting screws.

how does the bad sunroof mechanism sound like and how to manually close the sunroof if its stuck video

how to fix the skipping sunroof motor for free video

how to remove the headliner to access the sunroof motor

“to extend the lifetime of the sunroof mechanism occasionally clean and put grease on the moving parts”


You have to keep in mind that this is not just some kind of an average car, so there is a huge amount of wiring, switches, fuses, relays, modules and other magical electronic boxes which controls God knows what. However generally speaking – the various electronic issues can occur mostly on the before facelift cars – but I have to add that they are not that common as you would think. Either way, to minimize these problems keep the battery, the alternator + the batteries in a very good condition!

This Mercedes can be equipped with 1 or 2 main batteries. The first battery is always located under the hood – on a regular visible place. But if the car is equipped with 2 batteries then the second is located in the trunk-behind the trunk rear carpet panel. And actually there is also a 3rd smaller auxiliary battery under the driver’s side dash which can be weak too. All in all, just make sure that all of these batteries are in good condition, because if one of them is weak then you can get various electronic glitches, warnings or you won’t be able start the car. how to replace the small auxiliary battery video

“if you have plenty of free time then you can look at this thread for more information about the batteries”

“and if you got even more of free time then you can read thru the owners manual of this Mercedes here

-Then there is alternator which is not famous for premature failure, although it can be of course more often worn because of the bigger load it has to bear. On the other side there are more cases of faulty voltage regulator behind the alternator which will cause voltage fluctuation, and that’s not good. It’s not good because the voltage fluctuations/undervoltage will cause various electronic issues, and some say that this is the main cause of issues with the ISM for example!

And what is ISM?

ISM is the electronic gearbox selector module which can fail mainly on the before facelift cars – causing a situation in which you won’t be able to shift between the basic gears-PRND. There is no mechanical connection between the gearbox and the gear selector, so if the ISM gets stuck in Drive and the engine is off – then you won’t be able to start the engine. This magical ISM module is mounted on the side of the gearbox which means, that you will have to raise the car to access it. But actually, in some cases it’s enough to recalibrate this module using a diagnostic computer to make it work! However, if you will need to replace it then be prepared that this is not a plug and play procedure, so this part has to be programmed specifically to your car!

Other stuff

Moving on, there are also cases when you have various electrical issues at the same time like: not working or intermittently working windshield wipers, not working AC, not working power windows, power seats and so on. Well, in this case there is a very high chance that the fuse module under the hood will be faulty. This module contains fuses-which can fail, relays-which can fail, metallic plates-which can cause issues, and there is also the SAM module next to it-which can fail too.

You can’t start the car but the batteries, fuses and the SAM modules are ok? In this case you have most probably a bad starter motor.

However listen, as I said the various major electronic issues are not extremely common so there is no need to start to panic yet. So if:

  • your battery + alternator are in good condition
  • the water has not leaked into these magical electronic things
  • the wiring is not damaged
  • and if nobody has spilled some drinks onto the interior switches

then all these things are usually working in peace in the background. On the other side, because of the big amount of electronic features you really should take your time and inspect everything before buying.

And of course I have to mention the regular stuff which can break too like the: window regulators, the well-known keyless entry door handles, electronic parking brake or door locks – so additionally don’t forget to check these things.

Water leaks into the interior

As the other cars, this S class can also have issues with water leaks into the interior so as always don’t forget to check carefully for traces of water in the footwell area and on the headliner!

There are 2 main causes of these leaks:

1. water drains under the windshield

-First, there are the water drains under the windshield. Two drains are under the hinges and 2 drains are in the middle, but mostly the side drains and the first middle drain can clog over time causing the water to overflow over the plastic scuttle panel. This is not exactly good since the battery, the interior air intake and also the fuse box with the SAM electronic module are in this area. The water can reach all these things and of course it can leak into the interior. And by the way you should inspect specifically the air intake itself with a flashlight as well, since there is an additional drain at the bottom of this air intake. This drain is a rubber grommet which can clog – causing the water to accumulate here and leak into the blower motor and into the interior.

Next there is another similar rubber grommet, but this time on the lower part of the hood which drains the water into the second middle drain so make sure that this grommet is clean too.

But lets go back to the damn side drains under the hood hinges which are ending behind the wheel arch liners. The water will leak first in a collector on the inside of the liner, and just after this – out of the drain hole in the liner. The drain hole in the liner is too small (as you can see on the picture below) so it will clog with all the rubbish. Long story short, to properly clean the side drains you should partly remove the wheel well liners-to clean the drain itself and clean the rubbish in the liner collector as well.

2. sunroof drains

-Lastly there are the sunroof drains which can clog. There are 4 drains on the regular sunroof, but if you don’t want to remove the headliner then you will be able to access only the front drains, so use some fish tape or edge trimmer line to carefully clean these drains. The panoramic sunroof on the other hand doesn’t have any drains – at least it looks like there are none, but if I’m wrong about this then correct me in the comments.


This Mercedes can be equipped with 2 types of suspension:

  • Airmatic adaptive air suspension (standard)
  • Active ABC hydraulic suspension (standard for S600 and for all the AMG versions, optional for S450, S500, S550, S420 CDI, S450 CDI)


-This is a regular self leveling air suspension which is obviously comfortable, but you can adjust it from comfort to a bit stiffer sport mode as well, and you can raise the car a little with a button on the dash.

“In the before facelift cars you can put the suspension from comfort to sport mode only with the button on the center console, which means that in this case the sport mode of the suspension will be activated only with the sport mode of the gearbox at the same time. On the other side in the newer facelifted cars you can adjust the suspension to sport mode by pushing the sport button on the dash which means that in these newer cars you can adjust the suspension and the gearbox characteristics separately”

It’s all great and awesome, but there are the well-known air suspension parts which will sooner or later break, so: mainly the air compressor can more often wear out, the air struts can start to leak anytime basically-although still mostly on the before facelift cars, and rarely one of the air pipes can crack a little and leak. All of this means that you should definitely keep extra money to replace at least half of these parts. However replacing the air struts or the air compressor is actually not hard at all, and while the genuine parts are obviously expensive, there are also refurbished or new aftermarket struts and air compressors available for a much lower price + there are the very cheap air compressor repair kits available too.

Before buying:

  • It’s good to test the air suspension by at least raising and lowering the car a couple of times
  • Make sure the car is raising at a noticeable speed and the compressor is not very noisy! (the air compressor is located behind the front fender on the right side)
  • Check if the car is standing in level
  • Inspect the struts visually for damage
  • And keep in mind that the suspension should not lower even after a week of sitting!


-But let’s move on to the ABC active hydraulic suspension which is also comfortable, adjustable and self leveling. To top of that, compared to the airmatic it significantly reduces the body roll in all situations. So while the adaptive air suspension slowly adapts to the various situations, the active hydraulic suspension very quickly actively adapts to the situations-it actually adapts 5 times/second they say!

All the AMG and V12 models are STANDARDLY equipped with this ABC suspension.

And again, it’s all great and awesome but the maintenance and repair costs of this suspension are higher than in cars with the conventional airmatic setup. Although I have to add that this ABC suspension is more reliable than in the previous generation of this S class, and it can actually withstand more than 200 000 km without issues – but this of course doesn’t mean that there are no weak points.

Instead of air, this ABC suspension uses hydraulic fluid which is under high pressure. The fluid is distributed by numerous lines thru the valve blocks into the accumulators and shocks. The pressure is maintained by a main pump which is mounted on the front of the engine.

And this pump can be faulty. So if you hear various whining, howling or grumbling noises (turbine like, turbocharger like sounds) from the pump and you feel a vibration in the interior and especially in the steering wheel at idle-up to approximately 2000 RPM, then most probably the pulsation dampener mounted on this pump is faulty. The pulsation dampener is there to even out the vibrations in the fluid from the pump, so that’s why when it fails you get the already mentioned symptoms. The good thing is, that this part itself is not that expensive, however in cars equipped with the V8 engines there is very little space around the pulsation dampener, so it’s harder to replace it, which means that you have to: release the engine mount-remove the whole pump-and just then replace the pulsation dampener itself. On the other side the paradox is that in cars with the V12 engines the pulsation damper can be replaced easily without removing the whole pump!

Interestingly, sometimes the expensive pump itself can be worn as well. But you have to remember that not only the ABC pump but also the power steering pump is combined in this single unit, so it is complex and expensive. However you can have it refurbished for a much lower price, or you can buy a used pump if you like to gamble.

Then there are the lines which can crack/burst and leak, and not only because of the age or faith, but also because of the road salt which will cause corrosion on them. So before buying check not only for the already mentioned pump noises but also for leaks from these pipes, and especially check the lines in in front of the engine since one of them can burst more often and dump all the fluid out.

“Keep in mind that if one of the oil line bursts and your pump will run on low or no fluid at all – even for a very short time, then there is a very high chance that the pump gets permanently damaged and it starts to make the already mentioned noises!”

On the other side not only the pipes, but also the shock absorbers themselves can start to leak. However I have to add that this is not like extremely common and mostly still just the before facelift cars are affected because of the age. But if the shock is just misting oil then there is no need to panic, just check the fluid level regularly (the misting can actually remain the same for a couple of years without getting worse, so you can leave it like this with no worries – just occasionally check it if its not getting worse). However if it starts to visibly drip oil and you can see that the oil level is slowly decreasing then you should replace the shock in the near future! Nevertheless, be mentally prepared that one brand new ABC shock absorber costs approximately the same as the new pump, although again because of the high price there are also remanufactured shocks available which are cheaper. + if you have like really bad quality roads in your country then be prepared that the strut in these shocks can break-there are already some cases of this (yes there is a regular strut in these special struts, and if the strut breaks then the car will handle like garbage, obviously)

Issues with the stiffness of this ABC suspension can occur too, which means that in some corner the shock will be stiff while the others remain soft/comfortable, or the whole suspension becomes stiff-this can be caused by faulty acceleration sensors on before facelift cars

stiff ABC suspension on before facelift cars can be caused by faulty acceleration sensors more info here

To minimize issues with the various components of this complex suspension and to extend its lifetime – you should definitely replace the hydraulic fluid and filter in this system every 4 years or 60 000 km and check the fluid level regularly. By the way if you want to replace the ABC filter then keep in mind that you can’t order it for the w221 separately. However the filter is identical with the W220 models which can be actually ordered separately, so just order the filter for the W220 models and put it in your W221.

how to replace ABC fluid video , the tool to flush the system

To finally end the issues list, both of the suspensions do have height sensors which are usually ok, just the leveling arms attached to them can seize up or pop out over time causing suspension related fault codes or the car will stand unevenly. So check those damn height sensors dude!

Cars equipped with the Airmatic do have a visible air line on top of the front shocks and cars equipped with the ABC don’t have anything on this place, so if you are looking for an S class then you can quickly and easily check which suspension the car has.

The other suspension components: control arm bushings, ball joints, tie rods so all that usual shit can fail before 100 000 mi – so be prepared to replace this stuff before this mileage point and check for all those usual noises from the suspension.

“A creaking sounds from the front can be from the front sway bar bushings”

on the next page: ENGINES, TRANSMISSIONS


  1. Great review

    I own this car myself. 2012 model with the 4.7 engine and 4matic lwb. Greatest car i have ever owned.

    Unfortunately owning this car has not been cheap. I was unfortunate enough to get the dreaded “M278 bonus issue” mentioned here(worn cylinder walls). and thus had to get a new engine. Mercedes does not sell only the block. This was extremely expensive i was fortunate to know ppl and get a good used engine only 20000km on it. But if i was to do this at the Dealership they would have charged around 75000euro just for the engine alone. This being a brand new engine. The nice thing is at least the car will last even longer now.

    Before the engine problem the control unit for the radio broke. This not only runs the radio but also the car “modes” and pretty much all other functions of the car, you can drive the car but not use any of it’s functions. Mercedes will not repair the radio unit and will only sell you a new one at the price of 10000euro. And since this is a very special unit and coded to the car you can not just buy a used one. And not many will repair this unit since it is quite advanced and unusual in the way it runs fiber optic cables in the car. Luckily Braybrooks in England will repair this unit for a fraction of the price. I could only find one other company that would repair this radio unit, that was in USA and that is to far for me. The unit might never brake, still something to keep in mind.

    Aside from those two problems i have had no other issues with the car. Service is surprisingly cheap even at the dealership.

    Tough if you only want this car for the ride and equipment i would definitely go for a diesel. As far as i know these tend to have less problems and when they do, less expenses. But with that being said it will never be the same as a V8 🙂

    Still with all the problems i faced with the engine and radio unit i will never regret owning this car and will continue to own it for a long time.

  2. love your reviews. love the random swearing. as i read this i hear your voice bitching about the issues lol. keep at it. great place for NO BS info. though i cannot figure out why my car jerks or chugs on reverse and forward on cold start.

  3. I’m glad you mentioned the drains issue, that has been a pain. I replaced the resistor pack, corroded from water damage, the AC won’t come on, can this be a burned out connector. It’s also slow draining my battery. The old one was killed by the water issues.


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