BMW M5 E39

The S62 uses a dual VANOS system (intake and exhaust) that is virtually guaranteed to need attention on any car of this age. Pre-October 1999 cars lack set screws in the solenoid covers, making vibration damage more likely. There are two types of VANOS noise: a cold-start rattle that stops within a minute (caused by the oil pressure accumulator bleeding off overnight, fixable with an updated accumulator), and a rattle that worsens as the engine warms (requires internal rebuild). BMW acknowledged the issue and offered free accumulator replacement until December 2003. A full VANOS rebuild with new seals, cleaned oil passages, rebuilt oil pump, and tested solenoids costs €800-1,200 at a specialist using rebuild kits from Beisan Systems or Dr. Vanos. Dealer replacement of both complete units can reach €3,000 or more. While a noisy VANOS is primarily annoying rather than damaging in the short term, it does reduce low-RPM torque and should be addressed.

The S62, like other BMW M engines (S54, S65, S85), was built with bearing oil clearances tighter than the performance engine industry recommends. Combined with manufacturing tolerance stacking, some engines end up with borderline clearances. This makes the S62 sensitive to oil quality and change intervals. Catastrophic failure is uncommon on the S62 compared to the S65/S85 engines, but it does happen, particularly on cars with extended oil change intervals or heavy track use. Symptoms include a faint ticking at idle and metal particles in oil analysis. Preventive rod bearing replacement is recommended between 120,000-180,000 km (80,000-120,000 miles). Many engines run well past 300,000 km on original bearings with diligent oil changes. Parts cost approximately €400-500 for all 16 bearings, but labor is extensive (engine-in-car service requires 15-20 hours). Total cost at a specialist runs €2,000-3,500. Regular oil analysis through services like Blackstone Labs is an effective early warning system.

The S62 throttle actuator uses plastic internal gears that become brittle and wear over time. When they fail, the engine enters limp mode with DSC and EML lights illuminated. Genuine new actuators are priced above €2,000 and becoming increasingly difficult to source as BMW discontinues older M parts. Rebuild services from specialists like EBM Engineering offer a more practical alternative at €500-800, replacing the worn gears with upgraded motorsport-grade materials. The rebuild is done on the customer's original unit and includes full inspection. Labor for removal and reinstallation is approximately 3 hours. This issue can occur at any mileage but becomes more common beyond 150,000 km.

Every E39 M5 cooling system is now over 20 years old, and plastic components degrade with age regardless of mileage. The expansion tank is the most common failure point, with the plastic becoming brittle and cracking at connection points. The original water pump used a plastic impeller that could disintegrate (updated to composite material in revised parts). Thermostats stick, hoses become brittle, and radiator end tanks can crack. A complete cooling system overhaul (radiator, water pump, thermostat, expansion tank, all hoses, coolant) costs €500-800 in parts. With labor, expect €800-1,500 at a specialist. Many owners upgrade to an aluminum radiator and Stewart EMP water pump for roughly €1,200-1,500 in parts for a more robust system. Any car that has not had its cooling system refreshed should be treated as an imminent failure risk. An overheating event on the S62 can cause head warping and catastrophic damage.

The rear subframe bushings on the E39 M5 are fluid-filled rubber units that deteriorate over time. Once the fluid drains, the bushings offer no damping, resulting in a noticeable clunk from the rear when transitioning between acceleration and deceleration. The front differential mount bushing is often the first to fail (typically 120,000-150,000+ km). A failed differential bushing allows the diff to move excessively, which can tear CV joint boots and cause further damage if ignored. Repair requires dropping the rear subframe and differential. The original failed bushing design used a hard resin center that banged against the sleeve once the rubber failed. Updated replacement bushings eliminate this resin center. Parts are relatively inexpensive (€200-400 for a full set), but labor is 8-12 hours due to subframe removal. Some owners add reinforcement plates during the job. Total cost at a specialist: €600-2,000 depending on scope and whether additional items (control arms, trailing arm bushings) are addressed simultaneously.

The S62 cylinder heads have narrow secondary air injection passages that clog with carbon deposits over time. The secondary air pump check valve is the most common failure point: when it sticks open, exhaust gas enters the pump during off periods and eventually destroys it. Fault codes P1421 and P1423 (Secondary Air System Flow Too Low) are the typical symptoms. Replacing the pump and check valve is straightforward at €500-800. However, if the carbon buildup in the cylinder head passages is severe, repair requires disassembling the top end of the engine, pulling the cylinder heads, and mechanically cleaning or drilling out the carbon. This comprehensive repair can reach €2,000-3,000 and take several weeks.

This is a well-known E39 platform issue affecting the M5 and all other E39 models. The ribbon cable connecting the LCD display to the circuit board degrades over time, causing progressive pixel loss in the odometer, temperature, and on-board computer displays. Nearly all E39s of this age will show some degree of pixel loss. Specialist repair services replace the ribbon cable and restore full display functionality for €150-250. DIY repair kits cost approximately €30 but require careful soldering. Complete cluster restoration including all LCD segments and optional gauge ring upgrades runs €250-400. This is a cosmetic issue that does not affect drivability.

The S62 uses two mass airflow sensors (one per bank). They degrade gradually from contamination by dirt, oil vapors, or residue from aftermarket air filters. Symptoms range from subtle power loss and reduced fuel economy to severe sluggishness and limp mode. A simple diagnostic test: unplug one MAF connector before starting. If idle improves compared to previous poor running, that sensor needs replacement. The overwhelming consensus on M5 forums is to use only OEM Bosch sensors, as aftermarket alternatives cause calibration issues on the S62. Replacement cost per sensor is approximately €150-300, and both should be replaced as a pair. Labor is minimal (under 1 hour).