The 2007 Mercedes-Benz S550, while initially lauded for its luxury and performance, gained notoriety for a critical engine flaw. This issue, stemming from defective balance shaft and timing chain gears, impacted various V6 and V8 Mercedes models in the 2006-2007 production years. Understanding this problem is crucial for anyone considering a used S-Class, especially those eyeing the seemingly attractive prices of older models. This article will delve into the specifics of this issue, focusing on why choosing a 2008 or later S550 is essential.
The Ticking Time Bomb: Faulty Gears in the M272 and M273 Engines
The heart of the problem lies within the M272 (V6) and M273 (V8) engines. Mercedes-Benz, in a cost-saving measure, used subpar metal for the balance shaft gears in the M272 and a similar gear connected to the timing chain in the M273. Over time, these gears would wear down prematurely, leading to potentially catastrophic engine failure.
Initial symptoms might include a check engine light accompanied by camshaft timing codes. Ignoring this warning could lead to noticeable engine vibration, progressing from a subtle tremble to a violent shaking as the gear deteriorates further. If left unchecked, the timing chain could slip, causing pistons to collide with valves, ultimately destroying the engine. Imagine your luxurious S-Class rendered immobile, requiring a costly engine replacement or extensive repairs.
The Costly Repair: A Financial Nightmare
Replacing the faulty gear isn’t a simple task. In the S550’s V8, accessing the gear requires a significant engine teardown. Mechanics need to remove numerous components, including the engine itself, front cam covers, secondary air pump, various pulleys and housings, and ultimately the timing cover. Reassembling everything correctly adds to the complexity and labor costs.
Dealership repairs could easily run into thousands of dollars due to the extensive labor involved. Even for the more mechanically inclined attempting a DIY fix, the process is incredibly labor-intensive and requires specialized tools and knowledge. In some cases, particularly with less valuable models like a 2006 C-Class, the repair cost could exceed the car’s worth. Replacing the entire engine with a used one is another option, but still carries a hefty price tag of around $5000 for the engine plus approximately $1500 for installation.
The Solution: Opting for a 2008 or Later S550
The good news is that Mercedes-Benz addressed this issue in the 2008 model year. The company rectified the problem by using a more durable material for the gears, effectively eliminating the premature wear issue. They also settled a class-action lawsuit related to the faulty gears. Therefore, choosing a 2008 or later S550 significantly reduces the risk of encountering this expensive and debilitating engine problem. Ensuring the engine serial number falls outside the affected range offers further peace of mind.
Conclusion: Buyer Beware, Choose Wisely
While a pre-2008 S550 might seem like a tempting bargain, the potential for catastrophic engine failure due to the balance shaft and timing gear issue makes it a risky proposition. The considerable repair costs associated with this problem can quickly turn a dream car into a financial nightmare. To avoid this potential headache, prioritize a 2008 or later S550. Mercedes-Benz corrected the defect in these later models, providing a more reliable and enjoyable ownership experience. Remember, a little research and careful selection can save you from significant expense and frustration in the long run. Don’t let a seemingly good deal turn into a costly mistake.
