2008 BMW M5 - Common Problems & Maintenance Guide

The Sequential Manual Gearbox hydraulic pump and accumulator commonly fail, causing rough shifting, inability to select gears, or complete transmission failure. Symptoms include grinding noises, delayed engagement, and warning messages on the Control Display.

The variable valve timing system can develop issues with solenoids and actuators, leading to rough idle, reduced power, and check engine lights. Common on high-mileage vehicles due to oil contamination and wear.

The S85 V10 engine is prone to premature rod bearing wear, especially in vehicles driven hard or with extended oil change intervals. This can lead to catastrophic engine failure if not addressed promptly.

Various ECUs including the SMG control unit, engine management, and comfort access modules can fail, causing multiple warning lights and system malfunctions. Often requires professional diagnosis and programming.

The high-pressure fuel pump can fail causing poor engine performance, rough running, and potential stalling. More common in vehicles with higher mileage or poor fuel quality usage.

How reliable is the 2008 BMW M5 SMG transmission?

The SMG transmission is known for durability issues, particularly with the hydraulic pump and accumulator. Regular maintenance every 60,000 miles and proper driving techniques can extend its life, but many owners eventually convert to manual transmission due to high repair costs.

What is the typical fuel economy for the 2008 M5?

The M5 typically achieves 11-13 mpg in city driving and 17-19 mpg on the highway. Aggressive driving can significantly reduce these numbers due to the high-performance V10 engine's fuel consumption characteristics.

How often should I change the oil in my 2008 M5?

BMW recommends 10,000-mile intervals, but many enthusiasts and mechanics suggest 5,000-7,500 miles for the S85 V10 engine, especially given the rod bearing wear issues. Using high-quality synthetic oil is essential for engine longevity.

What are the warning signs of rod bearing problems?

Early signs include a metallic knocking noise at idle that worsens with RPM, oil analysis showing elevated copper levels, and occasional rattling during cold starts. Immediate inspection is critical as failure can destroy the engine.

Is the 2008 M5 expensive to maintain?

Yes, maintenance costs are significantly higher than regular sedans due to specialized parts, complex systems, and required BMW dealer or specialist service. Annual maintenance can range from $3,000-$8,000 depending on needed repairs.

Can I drive the M5 in winter conditions?

While possible with proper winter tires and cautious driving, the M5's rear-wheel drive and high power make it challenging in snow and ice. The DSC system helps, but winter driving requires significant skill and appropriate tires.

What should I look for when buying a used 2008 M5?

Check for complete service records, especially SMG and oil change history. Have a pre-purchase inspection focusing on rod bearings, VANOS system, and transmission. Avoid cars with modified engines or evidence of track use without proper maintenance.

How does the iDrive system work in the 2008 M5?

The iDrive system controls navigation, entertainment, climate, and vehicle settings through a central controller and display. While considered complex initially, it allows comprehensive vehicle customization and provides detailed vehicle information and diagnostics.

What is MDrive and how do I use it?

MDrive allows you to save personalized settings for engine response, transmission behavior, suspension, and other systems. Press the M button on the steering wheel to activate your saved preferences for a more customized driving experience.

Are there any recalls for the 2008 BMW M5?

Several recalls have been issued over the years, including fuel pump issues, airbag problems, and various electrical concerns. Check with BMW or NHTSA database using your VIN to verify if your specific vehicle has outstanding recall work.