Mercedes-Benz CLS-Class II c run: a new V6 with old timing problems and a V8 with chances for badass
The second-generation CLS, featuring a much greater variety of versions compared to the first (here, four-wheel drive, and even station wagons), turned out to be a machine in general not very lomuchey, but requiring attentive and quality service even at the age of 5-7 years. Including, as we explained in detail in the first part of the review, on the part of the body.
A set of power units, at first glance, looks frightening. Less than 7 steps in the boxes does not happen, and after restyling them already 9! Motors entirely powerful and complex … But frankly unsuccessful can only be considered a V8 – the rest is expensive to maintain, but with proper care it takes a long time.
The mechanical part of the transmission does not cause much trouble: a good resource for drive shafts, gearboxes and constant velocity joints. All-wheel drive versions, which the second-generation CLS, unlike the first, have, have difficulties with the intermediate shaft of the front axle.
The shaft passes directly through the channel in the engine crankcase, and together with the front axle reduction gear attached to the crankcase, they become very hot. As a result, wear out quickly and, moreover, the half-axle bearings in the engine crankcase sour. The front gearbox itself may leak due to aging of the oil seals. Repair in this case is difficult, you can damage the light-alloy crankcase when replacing bearings. A typical symptom of problems is vibrations on the steering wheel when driving, often subtle.
With the transfer case 4Matic, there are no problems until at least 200-250 thousand mileage, provided that every 60 thousand oil was updated in it, and its level was monitored all this time. After 200-250, if you are the responsible owner, it makes sense to disassemble the box and check the condition of the bearings and chain tension. And if you went quietly, then it is very likely that the state of both of them will be good.
A different picture in the AMG-versions. Razdatka and gearbox they nominally their own, but the construct is very similar to the “normal” version – apparently, the gain was not enough for the torque motors, so that with the active “piling up” the first problems with the shaft joints can start even up to 100 thousand mileage.
The main automatic transmission of cars before restyling is a seven-speed box 722.9 in its later version, with a modified mechatronic and box control on the steering-wheel lever. In AMG-versions, by the way, the lever box in the usual place, but there the unit itself is significantly different.
Due to the fact that by 2011, the main problems of the AKP 722.9 series (described in detail in, say, the recent W211 material) have been solved, there are no serious mechanical problems. Both the mechatronic unit and the cooling unit were substantially improved. If, again, to go quietly, then even with the standard service interval of the automatic transmission with oil change, every 60 thousand is able not to cause trouble at least until it runs at 150, or even 200 thousand kilometers. Next comes the repair period for the torque converter (DGT), mechatronic cleaning, replacement of rubber pistons and seals, as well as replacement of the box heat exchanger. If the owner is a racer, then the resource of the lining of the blocking of DGT can be 2-2.5 times less.
BECAUSE with absolute probability that the previous owner (or even a couple of add) traveled solely on Sundays at CHURCH, NOT, AND EXPECTED TO 250-thousandths RESOURCE UNCONDITIONALLY is not worth.
Repair of the torque converter with the replacement of the lining blocking at this automatic transmission is recommended to be performed proactively, when it arrives for repair for any other reason. If the pads are demolished and the oil is contaminated with an adhesive layer of the pads, then it will probably be easier to replace the mechatronics assembly (laying a budget of about 1,500–1,700 euros). Also on the chain can get critical wear and friction.
Now – to less noticeable problems 722.9. There are failures of the electronic control board of the box – first of all the speed sensors. The price of the fee in the collection is about 850 euros. Theoretically, you can solder a new sensor instead of a failed one, but this requires an electrician with good qualifications – it’s better to look for a recommendation.
Servo drive failures (ISM) boxes also remain a typical but rare malfunction. If the box does not switch modes, then maybe it’s in it.
A separate line can be mentioned some “innate features” and difficult to diagnose software and sensor glitches. This manifests itself in the form of kicks under load, when a lock is triggered or gear changes – this happens even on small runs. In general, a certain percentage of dissatisfied owners remains, but there are very few of them compared to what happened when the early 7G-Tronic appeared.
After the restyling of 2014, new 725.0 series boxes were also installed on the cars. A new series of boxes has nine steps, a lightweight mechanical part and a slightly reduced work temperature.
A full list of typical problems of this unit is not ready yet due to the youth of the design, but some features can already be listed.