Mercedes-Benz CLS 350 Review

Mercedes-Benz CLS 350 Review


The CLS is yet another vehicle from Mercedes-Benz, which gave birth to a new body style that went on to find favour with almost every direct competitor. Back in 2003, the CLS four-door coupe came through as an eye-catching car and found favour among many for its new design. With the CLS, the German automotive giant tried combining the best of two worlds – coupe and four-door saloon. Did they succeed? The answer is a clear affirmative and since October 2004, about 170,000 units of the CLS have moved out of showrooms globally.


The second-generation CLS is a lot different than its predecessor but carries over the same basic DNA – coupe + four-door saloon = four-door coupe. We tested the car recently in various conditions to know if those changes have still kept the core DNA of the first-gen car alive and how well do the new technologies work to justify the CLS’s Rs 68+ lakh price-tag. Read on to know if the CLS is just a rich man’s swanky showpiece, or a mechanically sound, yet pretty-looking car.


  1. Up to 25 % more fuel-efficient and 13 % aerodynamically-efficient than its predecessor.
  2. Each headlamp consists of 71 LED lamps.
  3. First car to feature individual rear seats with ISOFIX mounts.
  4. AIRMATIC suspension automatically lowers the body by 15 mm at speeds over 140 km/hr.


For most cars that we review, our primary focus is on the powertrain and suspension. With the CLS though, the main talking point is its design. It would be safe to say that the CLS’s strongest-selling point has been its design. According to a new car buyer survey in Europe sometime in 2003-04, 64 % of CLS customers in Europe chose it for its design. The 2nd-gen CLS isn’t as radically styled as its predecessor but still commands a significant road presence and appeal.


An oncoming CLS will always have onlookers glued onto the “C” shaped LED lights. Then there’s a long and neatly sculpted hood, followed by a rakish windscreen tapering off to a short boot, all helping with the coupe-ish look. The overall styling has been done extremely well and it’s hard to find a viewing angle from which one could find any oddities in the free-flowing design. The overall design theme resembles the 2nd World War fighter planes, long snouts and stubby rears.

The Day-Time Running Lights (DRL) technology used in the CLS is worth a mention here. The LED cluster in each headlamp unit is made up of 71 LED lamps and is paired with Adaptive Highbeam Assist to offer one of the most advanced headlamp systems in the world.


Full-LED headlamps possess many advantages over bi-xenons as they last longer and hence result in lower operating costs over a long-term. LEDs feature a colour temperature of 5,500 k (Kelvin) compared to the xenon’s 4,200 k, which brings them closer to the 6,500 k of daylight. It is this proximity with daylight colour, which offers better brightness and lesser strain on an oncoming driver’s eye.

Ever since Mercedes has passed on the SLS AMG’s design language to its other cars, the overall design appeal has upped significantly. Needless to say, with SLS AMG’s styling cues mixed with long, sloping and free-flowing lines, the CLS is a pretty car to look at from almost any angle.



Efforts to make cars lighter have reached levels, where it wouldn’t be wrong to recognise the word ‘light’ as a synonym for ‘car body’. Quite obviously, the engineers in Stuttgart tried to reduce weight wherever possible without compromising structural strength. As a result, the CLS is the first Mercedes to feature fully-aluminium frameless doors. These doors are about 24 kg lighter than conventional steel doors and are joined by a combination of gluing and riveting, instead of the normally-used welding technique.


Apart from the obvious efficiency benefits arising from lower-weight, there are ergonomic advantages too. Closing and opening the doors on an incline is much easier in a CLS than other cars of similar dimensions. While the European thud in the door has now diluted a bit, the strength hasn’t by any means. This door design meets the same seal requirement as for the heavier door frames on other Mercedes cars. In an internal test, these doors are subjected to high-pressure water-testing at 80 bar. In common man’s language, the pressure is five-times higher than that of an espresso machine.


The hood, boot lid, some suspension parts and various body support profiles too are made out of aluminium to reduce weight further.

To the human eye, the new CLS front fascia is wider than its predecessor but for the air it’s smaller. The CLS sports a drag coefficient of 0.26 %, a 13 % reduction over the previous generation despite the increase in overall dimensions. The lower numbers are primarily a result of cooling air louver, aerodynamically optimised wheels & underbody, and an overall body design conducive to free flow of air over it.



For some of the leading global carmakers, blue is the “in” word today, when it comes to clean and green technologies. Mercedes calls its green technology BlueEFFICIENCY, and through it aims to make lighter, powerful and efficient powertrains. The engine on offer in India is the 350 BlueEFFICIENCY, a 3.5 l V6 engine producing 306 hp and a torque of 370 Nm between 3500 and 5250 rpm.


This engine features the third-generation of direct petrol injection system, also known as the BlueDIRECT. The engines making use of this system are claimed to use up to 20 % lesser fuel through in-engine measures alone. Fuel-efficiency is claimed to be 14.7 kmpl in EU cycle but expecting figures anywhere close to that in India would be unfair. During our test, with a balanced mix of city and highway run, the on-board diagnostic (OBD) indicated an average fuel-efficiency of 9.6 kmpl.

BlueDIRECT injection features spray-guided combustion, a global-first in terms of series-production. Injection pressure has now been increased to 200 bar, resulting in higher power output and cleaner combustion of fuel.

In order to reduce weight, the crankcase, pistons and cylinder heads are made of aluminium. Further design-optimisation of these parts is claimed to reduce engine friction by 28 % over the earlier generation. Engine weight has been further reduced by implementing a 60° cylinder angle, which allows for the omission of balancer shaft. The angle further helps in reducing engine vibrations at high speeds and even while nearing the red line, the cabin is well-insulated from vibrations.

Few other technologies enhancing the efficiency are multi-spark ignition, resonance intake manifold, new-generation of piezo injectors and an improved thermal management system. The environmental effect of all these technologies working together is an appreciably-low 159 gm of CO2 emitted every km.



The 350 BlueEFFICIENCY engine is mated to a 7G-TRONIC PLUS automatic transmission. The transmission has been tweaked slightly, wherein the torque converter and the transmission unit have been optimised for better fuel-efficiency and driving comfort. The torque converter is claimed to provide better response and lower NVH levels due to a new hydraulic circuit. The mapping for the transmission in ‘ECO’ mode has been altered to maintain lower engine rpm while cruising. We found the transmission to be responsive and vibration free throughout our test cycle. In ‘Sports’ mode the transmission responds very well to ‘kick-downs’ and there is hardly any lag in response if one can maintain the engine rotation close to 2,000 per minute.


The CLS four-door coupe offers individual seats at the rear and hence seating for four passengers. There is ample space at the front and rear and despite the tapering coupe-ish roofline, the headroom is generous. The rear seats are very comfortable and offer a wraparound feel being individual units. Being a four-door coupe, the CLS needs to offer a sporty touch and the black leather all-around helps significantly towards the cause.


The instrument console’s highlight is the centrally stacked speedometer, which is likely to get the first attention owing to its classic design, bright display and a diameter of 109 mm. Mercedes claims they’ve given a wrap-around effect to the driver cockpit and we find no reason to disagree. The same effect has been carried over to the audio system, a Logic7 surround sound system developed by Mercedes-Benz in collaboration with Harman Kardon. A neat touch in the effort to provide a 360 degree experience is the placement of tweeters, which flank the centre-screen and do a great aesthetic job apart from their audible duties.

The overall cabin experience is a treat for the driver as well as the passenger regardless of the seating position. The CLS in our opinion strikes a good balance between a sporty yet classic and luxurious interior.



CLS features an AIRMATIC air suspension, which makes the ride quality very comfortable and works well on varied surfaces. The system is coupled with a variable damping system, which adjusts the damping force for each wheel based on surface and driving conditions. The automatic ride-height control ensures that the vehicle level doesn’t get affected by loading. This translates into better and predictable handling under varied load conditions. The ride height adjustment is a boon on Indian roads given the long wheelbase of the CLS. At the push of a button the driver can raise the ground clearance and the additional height is enough to tackle most of the obstructions found on our roads.


The CLS features a specially developed three-link front axle with McPherson struts. The differentiating factor from the E-Class is the inclusion of two individual links in the lower link plane, which are positioned at a steeper angle. This set-up is claimed to reduce body-roll and enhance cabin comfort. The rear suspension is an independent multi-link set-up, the same as the E-Class and has been designed to be as light as possible without compromising on rigidity.

The highlight of the CLS is that once rolling, the dynamics do not reflect much of the large dimensions. With the traction control deactivated and the ‘Sports’ mode engaged, the CLS feels like a much smaller car and is quite agile and responsive. A fairly direct steering helps spirited driving around corners but doesn’t provide much feedback. This can’t be termed as a drawback though given the car’s positioning.

The car’s low-NVH levels deserve a mention since at speeds of even 150 km/hr the wind whistle arising from the ORVMs and A-pillars is almost inaudible. The cabin is well-insulated from most surface undulations and it’s only the joints in a bridge or similar irregularities, which tend to funnel through to the cabin.



The CLS 350 is loaded with a wide array of active and passive safety features. An interesting active safety system is the Attention Assist, which observes driver behaviour to detect fatigue or distraction. The system does so using hi-resolution sensors and takes into account the steering movement to detect distraction. Attention Assist measures more than 70 parameters to determine driver behaviour. Based on these parameters and the hardwired data it creates a profile for each driver. If needed, the system can alert the driver through visual and audible prompts.


The car features dual-front, knee, side, curtains and pelvis airbags, taking the total count to nine. In addition, there are adaptive belt pre-tensioners and force limiters along with active head restraints. All electronic aids found in this price bracket are present on the CLS and the overall safety package is at par with the competition.


Some consider the CLS to be an E-Class with good-looking panels and S-Class equipment but the car is much beyond that. Our analysis of the vehicle’s technology makes it clear that right from the design, interior, suspension and powertrain, things were designed or altered for the CLS. This is a car for someone looking for a lifestyle vehicle with the best of luxuries and some sporty character to spice things up.


For years, automakers have produced vehicles, which aim at providing the better of two worlds in one package. Unfortunately, not many such vehicles have been received well by the customers, primarily due to the compromises made to include too much in too little. The CLS 350 though is in a different league. We find the CLS to be one of the best production vehicles that very successfully merges two body-styles and not just balances it out but provides the best from each world.

The CLS 350 BlueEFFICIENCY is priced at Rs 68.9 lakh, ex-showroom, New Delhi.


Text: Arpit Mahendra