MERCEDES 6420304617 Connecting Rod Piston Benz OM642 3.0L V6

( Manufacturer Part Number: 6420304617 ), ( Part Type: Rod Piston ), ( Manufacturer Warranty: 30 Days ), ( Country Of Origin: Germany )

Review MERCEDES benz 3.0l V6 Connecting Rod Piston #7 fits W211 W164 E350 ML350 2008

The **Mercedes-Benz 6420304617 (2008 W211/W164 E350 ML350 OM642 3.0L V6 Connecting Rod & Piston Set)** is a high-performance, precision-engineered component designed exclusively for the iconic **OM642 3.0-liter V6 diesel engine** found in the **Mercedes-Benz E350 (W211) and ML350 (W164)** models produced between 2006 and 2013. This critical assembly plays a pivotal role in maintaining the engine s structural integrity, efficiency, and longevity, ensuring optimal combustion, reduced wear, and sustained power delivery key factors for both daily driving and extended reliability. Crafted from **high-grade forged aluminum alloy** for the pistons and **heat-treated steel** for the connecting rods, this set is engineered to withstand the extreme mechanical stresses of high-pressure combustion cycles, turbocharging forces, and the demanding thermal loads inherent in diesel engine operation. The **precision-machined piston crowns** feature a **shallow dish design** optimized for the OM642 s combustion chamber geometry, promoting efficient fuel-air mixing and minimizing knock risk, while the **honeycomb-style piston rings** comprising a **top compression ring, a second compression ring, and an oil control ring** are designed to maintain optimal sealing under high-temperature conditions, preventing blow-by and excessive oil consumption. The **forged steel connecting rods**, featuring **I-beam cross-sections**, offer superior strength-to-weight ratios, reducing reciprocating mass and enhancing engine responsiveness while absorbing the cyclic loads generated by the crankshaft s motion. Each rod is **case-hardened and ground to exacting tolerances**, ensuring a snug fit with the **OM642 s 82mm stroke crankshaft journals** and the **wrist pin bores** in the pistons, minimizing lateral play and preventing premature wear. This set is a **direct-fit replacement** for the original equipment manufacturer (OEM) components, compatible with both **aftermarket and OEM crankshafts**, making it an ideal choice for restorations, rebuilds, or performance upgrades. Whether installed in a **stock OM642 engine** or a **modified high-torque application**, this connecting rod and piston set delivers the durability and performance expected from Mercedes-Benz s legendary diesel powerplant, ensuring reliable operation for thousands of miles with proper maintenance and lubrication.

### **Pros and Cons of Buying a 2008 Mercedes-Benz E350 ML350 (W211/W164, OM642 3.0L V6, Connecting Rod/Piston Issue)**

#### **Pros**

1. **Strong Engine and Performance**

- The **OM642 3.0L V6** is a well-regarded engine known for its smooth power delivery, torque, and reliability when maintained properly. In stock form, it produces **258 hp and 300 lb-ft of torque**, which is adequate for a mid-size luxury SUV.

- The **7G-Tronic automatic transmission** (if equipped) is a robust unit, though it requires proper servicing to avoid premature failure.

2. **Luxury and Comfort**

- Mercedes-Benz is synonymous with **premium interior quality**, offering high-end materials, comfortable seating, and advanced sound insulation.

- The **ML350 (W164)** has a more spacious and refined cabin compared to the E-Class (W211), with better rear legroom and a more upright driving position.

3. **Resale Value and Brand Prestige**

- Mercedes-Benz retains a strong **resale value** compared to many competitors, especially for well-maintained models.

- The brand carries **luxury cachet**, which can be appealing for buyers who prioritize status and exclusivity.

4. **Potential for Modifications**

- The **OM642** is a popular engine for tuning, allowing for **power upgrades** (e.g., turbocharging, ECU remapping) if the buyer is mechanically inclined.

- Aftermarket support is available for suspension upgrades, exhaust systems, and interior enhancements.

5. **Availability of Parts and Service Networks**

- As a **premium brand**, Mercedes-Benz has a **global dealer network**, making it easier to find parts and authorized service centers.

- Many **third-party mechanics** specialize in Mercedes repairs, reducing dependency on expensive dealership labor.

---

#### **Cons**

1. **Connecting Rod/Piston Issue (OM642 Common Problem)**

- The **2008 OM642 3.0L V6** is notorious for **connecting rod and piston failures**, particularly around **100,000 150,000 miles**.

- This is due to **design flaws in the piston design**, which can lead to catastrophic engine failure if not addressed.

- **Repair costs** can range from **$3,000 $6,000 **, depending on labor rates and whether the engine needs a full rebuild or replacement.

2. **High Maintenance and Repair Costs**

- Mercedes-Benz vehicles are **expensive to maintain**, with **premium parts, labor rates, and potential warranty gaps** (if not under factory coverage).

- **Transmission failures** (especially in older 7G-Tronic units) and **electrical gremlins** (e.g., sensor issues, infotainment problems) are common in this era.

3. **Fuel Economy and Environmental Concerns**

- The **3.0L V6 is not fuel-efficient** by modern standards, averaging **16 18 MPG combined** (city/highway).

- **Emissions regulations** may become stricter, potentially affecting resale value or requiring costly modifications in some regions.

4. **Reliability and Durability Concerns**

- While the **OM642 is robust**, it is **not as bulletproof as some modern engines** (e.g., the newer M276 V6).

- **Timing chain stretch** and **water pump failures** are known issues that require **proactive maintenance**.

- **Electrical systems** (e.g., ABS, airbag, infotainment) can be **unreliable**, requiring frequent diagnostics.

5. **Depreciation and Market Demand**

- The **W211 (E-Class) and W164 (ML-Class) are aging**, with **declining demand** compared to newer Mercedes models.

- **Insurance costs** may be higher due to the vehicle s age and repair complexity.

- **Financing options** may be limited compared to newer or more popular used luxury SUVs (e.g., BMW X5, Audi Q7).

6. **Potential for Hidden Damage**

- **Accident history** (especially in luxury vehicles) can be costly to repair, as **structural damage and alignment issues** are common.

- **Rust** (especially in older models) can be a concern in regions with harsh winters.

---

### **Ending Conclusion**

The **2008 Mercedes-Benz E350 ML350 (OM642)** is a **capable but high-maintenance luxury SUV** with a **strong engine when properly cared for**. Its **major drawback is the connecting rod/piston issue**, which can turn into a **financial burden** if not addressed early. However, if **budgeted correctly** (accounting for potential engine repairs), it can be a **rewarding purchase** for someone who values **luxury, performance, and brand prestige**.

For buyers who **prioritize reliability over luxury**, newer or more modern alternatives (e.g., **2010 BMW X5, Audi Q7, or even a well-maintained Lexus GX**) may be more practical. Meanwhile, **enthusiasts who enjoy working on their cars** or those who **plan to modify the engine** may find this a **fun project vehicle**.

---

### **Recommendation**

- **Get a full pre-purchase inspection (PPI)** from a **Mercedes specialist** to confirm the **engine s condition** (check for rod knock, compression, and oil consumption).

- **Verify maintenance records**, especially for **timing chain, water pump, and valve adjustments**.

- **Budget at least $5,000 $8,000** for potential **engine repairs** if the connecting rod issue is present.

- **Consider a lower-mileage example (under 100,000 miles)** if possible, as the **OM642 is more reliable in its early years**.

- **2010 2015 BMW X5 (N55/N63 engine)** More reliable, better fuel economy, and stronger resale.

- **2011 2017 Audi Q7 (3.0T V6)** Similar luxury, better turbocharged engine options.

- **2012 2018 Lexus GX** Extremely reliable, lower maintenance costs, but less performance.

- **Buy from a trusted seller** (e.g., a dealer with a warranty or a private party with full service history).

- **Plan for long-term maintenance** (oil changes every **5,000 7,000 miles**, timing chain inspection at **100K miles**).

- **Consider a warranty extension** if possible to cover potential engine issues.

**Can afford potential engine repairs**

**Value luxury and driving dynamics over absolute reliability**

**Are prepared for higher maintenance costs**

**You cannot budget for a $3,000 $6,000 engine repair**

**You prefer lower-maintenance, more modern alternatives**

**You prioritize fuel efficiency and long-term reliability**

For most buyers, **a newer luxury SUV with a turbocharged engine (e.g., BMW X5, Audi Q7) offers a better balance of performance, reliability, and value**. However, if you **love Mercedes and are willing to manage its quirks**, the **OM642 can be a fantastic driving experience** just **expect and prepare for repairs**.

Details:

Item will come as pictured. 2008 W211 W164 MERCEDES E350 ML350 OM642 3.0L V6 CONNECTING ROD WITH PISTON OEM. Warranty on electronic devices is void if identifying mark removed or has sign of tampering.

part #: 6420304617 prices

• $59.99-$269.95

specifications pistonringro:

• for models: W211, W164, E350, Ml350
• for makes: Mercedes
• for years: 2008
• mpn: 6420304617
• part type: Rod Piston
• manufacturer warranty: 30 Days
• country of origin: Germany

seller pistonringro:

• # reviews: 8929
• city: Tampa, Florida
• rating: 99.7%

returns pistonringro:

• paid by: Buyer
• time: 30 Days
• policy: Returns Accepted

offer pistonringro:

• options: Ship-to-home
• started: April 8, 2026
• quantity: 1
• availability: In Stock
• sold: 0

payments pistonringro:

• credit card: Mastercard
• wallet: Apple-pay
• other

general pistonringro:

• condition: Used
• Car Truck Parts Accessories > Engines Engine Parts > Pistons Rings

shipping pistonringro:

• type: Fixed
• service: FedEx Ground / FedEx Home Delivery
• transit: 3-7 Days
• cost: $13.00
• class: Standard
• carrier: FedEx

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