The 2007 Mercedes-Benz S550 was meant to be a pinnacle of luxury, a land yacht brimming with cutting-edge technology and unparalleled comfort. A decade later, these seemingly irresistible vehicles can be found at bargain prices. However, lurking beneath the veneer of opulence is a potentially catastrophic engine problem that could turn your dream car into a financial nightmare. This article delves into the critical issues plaguing the 2007 S550, specifically focusing on a small, yet devastatingly flawed component.
While the air suspension and complex electronics of this era’s Mercedes-Benz vehicles are known to be problematic, those issues can often be managed with regular maintenance and a skilled mechanic. The real Achilles’ heel of the 2007 S550 lies within its M273 V8 engine: a cheaply manufactured timing chain gear.
This seemingly insignificant gear, responsible for connecting the timing chain, is prone to premature wear and tear due to subpar metal quality. The teeth of the gear can decay and break off, leading to a cascade of disastrous consequences.
Initially, a check engine light illuminating with camshaft timing codes might be the only warning sign. Ignoring this crucial alert can lead to a progressively unbalanced engine, characterized by noticeable vibrations. Continued operation with a deteriorating sprocket will intensify the shaking, ultimately risking a complete timing chain slip.
Should the timing chain slip, the pistons will collide with the valves, resulting in catastrophic engine failure. A replacement engine can cost upwards of $5,000, with an additional $1,500 for labor, potentially exceeding the car’s current value. Suddenly, that “bargain” S550 becomes an expensive paperweight.
Even if you proactively address the issue before complete engine failure, replacing the faulty gear is an incredibly labor-intensive process. It requires complete engine removal and disassembly, including the front cam covers, secondary air pump, numerous pulleys and housings, and the entire timing chain system. Reassembling the engine correctly adds another layer of complexity and cost.
Dealer repair costs for this procedure can quickly escalate into the thousands due to the extensive labor involved. While the part itself is relatively inexpensive, the Herculean effort required to access and replace it makes this a costly endeavor.
This problem wasn’t limited to the 2007 S550. Mercedes-Benz models equipped with M272 V6 and M273 V8 gasoline engines manufactured during the 2006 and 2007 model years were potentially affected. The M272 V6 engines suffered from a similar defect in their balance shaft gears.
The likelihood of encountering this issue might not be astronomical, but the potential consequences are severe enough to warrant serious consideration. Is the risk of a catastrophic engine failure and a hefty repair bill worth the initial savings on a used 2007 S550?
The most prudent solution is to steer clear of potentially affected models and opt for a 2008 or later S550. Mercedes-Benz rectified the issue with improved gear materials in subsequent models, even settling a class-action lawsuit related to the defect. While no car is immune to mechanical problems, knowing the potential pitfalls of the 2007 S550 can save you from a costly and frustrating experience. Do your research, verify engine serial numbers, and prioritize a model year outside the affected range to enjoy the luxury of a Mercedes-Benz without the looming threat of a ticking time bomb under the hood.
