2008 Mercedes-Benz ML320
The 2008 Mercedes-Benz ML320 is a mid-size luxury SUV that offers a blend of comfort, capability, and style. The ML320 designation represents the diesel engine option. Other engine options available for the 2008 ML-Class include the ML350 (3.5L V6 gasoline), ML550 (5.5L V8 gasoline), and ML63 AMG (6.2L V8 gasoline). All engine options are paired with a 7G-TRONIC 7-speed automatic transmission. The ML320 features a 3.0L V6 diesel engine producing 215 horsepower and 398 lb-ft of torque. Many owners appreciate the comfortable ride, spacious interior, and overall luxury feel. Common complaints include the high cost of maintenance and repairs, as well as some electrical gremlins.
Engine
3.0L V6 Diesel (ML320)
- Oil Cooler Seal Leaks
- Description/Symptoms: Oil leak originating from the oil cooler area, often dripping onto other engine components. Visible oil under the vehicle. Burning oil smell.
- Solution: Replace the oil cooler seals.
- Estimated Cost to Fix: $300 - $700
- Recalls: None Found
- Glow Plug Failure
- Description/Symptoms: Difficulty starting, especially in cold weather. Check engine light illuminated. Diagnostic trouble codes (DTCs) related to glow plug malfunction.
- Solution: Replace the faulty glow plug(s).
- Estimated Cost to Fix: $200 - $500 (depending on the number of glow plugs needing replacement) *Recalls: None Found
- Diesel Particulate Filter (DPF) Issues
- Description/Symptoms: Reduced engine performance, increased fuel consumption, DPF warning light illuminated. Potential for limp mode.
- Solution: DPF regeneration (if possible), cleaning, or replacement.
- Estimated Cost to Fix: $300 - $2000+ (depending on the severity and required repair method) *Recalls: None Found
Transmission
7G-TRONIC 7-Speed Automatic (All Models)
- Torque Converter Failure
- Description/Symptoms: Shuddering or vibration at low speeds, especially during acceleration. Poor fuel economy. Transmission slipping.
- Solution: Replace the torque converter.
- Estimated Cost to Fix: $1500 - $3000+ *Recalls: None Found
- Valve Body Issues
- Description/Symptoms: Harsh or erratic shifting. Delayed engagement. Transmission slipping. Check engine light illuminated.
- Solution: Replace or rebuild the valve body.
- Estimated Cost to Fix: $800 - $2000+ *Recalls: None Found
- Conductor Plate Failure
- Description/Symptoms: Transmission stuck in limp mode. Inability to shift gears. Diagnostic trouble codes (DTCs) related to speed sensors or valve control.
- Solution: Replace the conductor plate.
- Estimated Cost to Fix: $600 - $1500 *Recalls: None Found
Suspension
- Air Suspension Compressor Failure (Airmatic)
- Description/Symptoms: Vehicle sagging or sitting unevenly. Air suspension warning light illuminated. Loud compressor noise or complete compressor failure.
- Solution: Replace the air suspension compressor.
- Estimated Cost to Fix: $800 - $1500+ *Recalls: None Found
- Air Strut Leaks (Airmatic)
- Description/Symptoms: Vehicle sagging on one side. Hissing sound coming from the strut. Deteriorating ride quality.
- Solution: Replace the leaking air strut(s).
- Estimated Cost to Fix: $800 - $2000+ per strut *Recalls: None Found
Electrical
- EIS (Electronic Ignition Switch) Failure
- Description/Symptoms: Key not recognized. Inability to start the vehicle. Steering wheel lock malfunction.
- Solution: Replace the EIS module. Requires programming by a qualified technician.
- Estimated Cost to Fix: $800 - $1800+ *Recalls: None Found
- SAM (Signal Acquisition Module) Issues
- Description/Symptoms: Intermittent electrical problems affecting various systems (lights, wipers, windows, etc.). Diagnostic trouble codes (DTCs) related to SAM malfunction.
- Solution: Diagnose the specific issue with the SAM and repair or replace the affected module.
- Estimated Cost to Fix: $300 - $1500+ (depending on the specific issue and required repair) *Recalls: None Found
- Battery Drain
- Description/Symptoms: Battery frequently dead or requiring frequent charging.
- Solution: Perform a parasitic draw test to identify the source of the drain. Repair or replace the faulty component causing the drain.
- Estimated Cost to Fix: $100 - $1000+ (depending on the source of the drain) *Recalls: None Found
Exterior
- Tail Light Assembly Leaks
- Description/Symptoms: Water accumulating inside the tail light housing. Bulb failures.
- Solution: Replace the tail light assembly or reseal the existing one.
- Estimated Cost to Fix: $200 - $600 *Recalls: None Found
- Power Folding Mirror Failure
- Description/Symptoms: Mirror does not fold properly, grinds, or makes noise.
- Solution: Replace the mirror assembly.
- Estimated Cost to Fix: $300 - $800 *Recalls: None Found
Interior
- Sunroof Malfunction
- Description/Symptoms: Sunroof not opening or closing properly. Sticking or binding. Motor failure.
- Solution: Repair or replace the sunroof motor, tracks, or other components.
- Estimated Cost to Fix: $300 - $1000+ *Recalls: None Found
- Climate Control Issues
- Description/Symptoms: Inconsistent temperature. One side blowing hot while the other blows cold. Blower motor malfunction.
- Solution: Diagnose and repair the climate control system, including checking the blend door actuators, refrigerant levels, and blower motor.
- Estimated Cost to Fix: $200 - $1000+ *Recalls: None Found
Summary
The 2008 Mercedes-Benz ML320 can be a comfortable and capable SUV, but it is essential to be aware of potential issues. The most prevalent concerns relate to the diesel engine’s oil cooler seals, glow plugs, and DPF, as well as the 7G-TRONIC transmission’s torque converter, valve body, and conductor plate. Air suspension problems are also relatively common. Electrical gremlins can manifest in various ways and can be difficult to diagnose. The severity of these issues ranges from minor inconveniences to major mechanical failures. Repair costs can be significant, especially for engine, transmission, and air suspension-related problems, making a thorough inspection before purchase highly recommended.