2012 maintenance schedule
2012 BMW 640i Convertible Complete Maintenance Schedule & Service Guide
The 2012 BMW 640i Convertible utilizes BMW's Condition Based Service (CBS) system.
Last updated
September 17, 2026
Reviewed for service schedule clarity.
Key Takeaways
- The 2012 BMW 640i Convertible (F12 chassis) is powered by the N55 3.0L turbocharged inline-six engine with an oil capacity of 6.5 liters and requiring BMW-approved 0W-30, 0W-40, 5W-30, or 5W-40 synthetic oil .
- BMW utilizes a Condition Based Service (CBS) system that calculates maintenance needs based on actual driving conditions rather than fixed intervals, with service data stored in the vehicle's remote key fob .
- Brake fluid requires replacement at intervals determined by the CBS system—typically a time-based service—and storage periods with the battery disconnected are not automatically accounted for .
- Oxygen sensors are scheduled for replacement at 120,000 miles with a repeat service at 150,000 miles .
- The N55 engine uses Bosch spark plugs as original equipment, with a recommended replacement interval of approximately 60,000 miles .
- The serpentine drive belt should be inspected at regular intervals, with belt manufacturers typically recommending replacement at 90,000 miles .
Understanding BMW's Condition Based Service (CBS) System
The 2012 BMW 640i Convertible utilizes BMW's Condition Based Service (CBS) system. The maintenance system directs you to required maintenance measures and supports you in maintaining road safety and the operational reliability of the vehicle . Unlike traditional fixed-interval maintenance schedules, CBS uses sensors and special algorithms that take into account the driving conditions of your vehicle to determine maintenance requirements. The system makes it possible to adapt the amount of maintenance you need to your user profile .
Service Data in the Remote Control: Information on required maintenance is continuously stored in the remote control. Your service center will read out this data and suggest the right array of service procedures for your vehicle. Therefore, hand your service specialist the remote control with which the vehicle was driven most recently .
Storage Periods: Storage periods during which the vehicle battery was disconnected are not taken into account. If this occurs, have a service center update the time-dependent maintenance procedures, such as checking brake fluid and, if necessary, changing the engine oil and the microfilter/activated-charcoal filter .
Engine Specifications & Capacities
The 2012 BMW 640i Convertible is equipped with the N55 3.0L turbocharged inline-six engine .
| Specification | Detail |
|---|---|
| Engine Code | N55B30A |
| Displacement | 3.0L L6 Turbo |
| Oil Capacity (with filter) | 6.5 liters |
| Approved Oil Viscosities | SAE 0W-40, 0W-30, 5W-40, 5W-30 |
| Alternative Oil Specification | API SM or higher |
Oil Quality Note: The engine oil quality is critical for the life of the engine. Only use approved BMW High Performance oil. No oil additives should be used, as they may lead to engine damage .
OEM Factory Maintenance Schedule
The following maintenance intervals represent the recommended schedule for the 2012 BMW 640i Convertible. Exact intervals are determined by the vehicle's CBS system based on driving conditions.
Service Intervals at a Glance
| Service Item | Interval | Notes |
|---|---|---|
| Engine Oil & Filter | CBS-indicated; typically 10,000-12,000 miles | Conservative recommendation: 5,000-7,500 miles |
| Brake Fluid | CBS-indicated; time-based service | Have updated after battery disconnection |
| Oxygen Sensors | 120,000 miles; repeat at 150,000 miles | Mileage-based replacement |
| Spark Plugs | Approximately 60,000 miles | Replace in sets of 6 |
| Serpentine Belt | Inspect regularly; replace ~90,000 miles | Or sooner if worn/noisy |
Engine Oil and Filter Change
The N55 engine requires BMW-approved synthetic oil meeting specific viscosity grades . BMW's CBS system will indicate when an oil service is due, with typical intervals around 10,000-12,000 miles or 12-18 months depending on driving conditions .
Conservative Owner Guidance: Motor oil is the single most important element in keeping your engine healthy. A conservative approach is to change synthetic motor oil more frequently than the CBS system indicates, particularly for vehicles subjected to:
- Frequent short trips
- Aggressive or spirited driving
- City driving conditions
Some third-party references suggest reducing the interval to approximately 5,000-7,500 miles for optimal engine protection. Always replace the oil filter at every oil change and check the oil level periodically .
Brake Fluid Service
Brake fluid service is a time-dependent maintenance procedure monitored by the CBS system . Storage periods during which the vehicle battery was disconnected are not taken into account; if this occurs, have a service center update the brake fluid service reminder .
Fluid Specification: BMW-approved brake fluid meeting manufacturer specifications. Consult your service center for the correct fluid type for your vehicle.
Conservative Owner Guidance: Brake fluid is hygroscopic—it absorbs moisture from the atmosphere over time, which lowers its boiling point and compromises braking performance. A conservative approach is to flush and replace brake fluid every 2 years regardless of mileage.
Oxygen Sensor Service
OEM Interval: Oxygen sensors are scheduled for replacement at 120,000 miles, with a repeat service at 150,000 miles . Oxygen sensors deteriorate on a mileage basis and replacement helps maximize fuel economy and minimize exhaust pollution.
Spark Plug Service
The N55 engine uses high-performance spark plugs to ignite the fuel-air mixture in the engine's combustion chamber . The 2012 BMW 640i Convertible uses Bosch spark plugs as original equipment .
OEM Part Number: BMW 12-12-0-037-582
Recommended Interval: Replacement should follow the vehicle maintenance schedule as indicated by the CBS system. A common recommendation is to replace spark plugs at approximately 60,000 miles .
Owner Guidance: Keeping your spark plugs fresh is an important part of maintaining engine performance. Signs that spark plugs may need replacement include difficulty starting, rough idle, reduced fuel economy, and misfire codes. Spark plugs should always be replaced in sets (the N55 engine uses 6 spark plugs) .
Serpentine Drive Belt Service
The serpentine belt drives vital accessories including the alternator, water pump, and AC compressor .
Recommended Interval: Belt manufacturers typically recommend belt replacement at 90,000 miles . However, the belt must be inspected for wear or damage at regular intervals prior to this high mileage.
Signs of Belt Wear: Cracking, glazing, squealing, or visible damage are signs it is time to replace .
Conservative Owner Guidance: Pay close attention to the belt's condition if you notice any unusual noises from the engine accessory drive. It is advisable to have the belt tensioner and pulleys inspected at the same time, as they may also require replacement.
Transmission Service
Owner Guidance: Although BMW's official schedule may classify the transmission as "lifetime fill" under normal conditions, third-party references recommend periodic transmission fluid service for long-term reliability . For vehicles driven in severe conditions, more frequent service may be advisable. The automatic transmission has an oil capacity of approximately 8.5 liters for a dynamic fluid exchange . If you are concerned about transmission longevity, consult your service center about an appropriate service interval.
High-Mileage Maintenance Considerations
For 2012 BMW 640i Convertible examples exceeding 60,000 miles, additional maintenance considerations become increasingly important.
Cooling System
The N55 engine uses a sophisticated cooling system with an electric water pump. Cooling system components should be inspected regularly as the vehicle ages.
Ignition Coils
Ignition coils transform battery voltage into the high energy needed for each spark plug . Weak coils or worn plugs can cause misfires, rough idle, hard starts, and poor fuel economy. A conservative approach is to inspect ignition coils when replacing spark plugs and replace them as a set if individual coils show signs of failure.
Convertible Top Mechanism
The retractable hardtop mechanism should be inspected periodically for proper operation and seal condition. While there is no specific scheduled maintenance interval, keeping the seals clean and lubricated can help prevent leaks and operational issues.
BMW Service & Warranty Information
Please consult your Service and Warranty Information Booklet (for US models) or Warranty and Service Guide Booklet (for Canadian models) for additional information on service requirements . Maintenance and repair should be performed by your service center. Make sure to have regular maintenance procedures recorded in the vehicle's Service and Warranty Information Booklet, as these entries are proof of regular maintenance .
Long-Term Ownership Outlook
With proper and diligent maintenance, the 2012 BMW 640i Convertible can achieve high mileage. The N55 engine is a reliable powerplant when properly maintained. Staying on track with routine service appointments helps maintain performance, safety, and resale value.
The BMW Maintenance System directs you to required maintenance measures and supports you in maintaining road safety and the operational reliability of the vehicle . Following the CBS system recommendations, combined with conservative preventative maintenance, will help maximize the vehicle's longevity.
Maintenance questions
2012 BMW 640i Convertible FAQs
How often should I change the oil in my 2012 BMW 640i Convertible?+
The Condition Based Service (CBS) system calculates the oil change interval based on driving conditions, typically around 10,000-12,000 miles or 12-18 months . A conservative approach is to change synthetic oil every 5,000-7,500 miles for optimal engine protection. The N55 engine has an oil capacity of 6.5 liters and requires BMW-approved 0W-30, 0W-40, 5W-30, or 5W-40 synthetic oil .
What type of oil does the 2012 BMW 640i Convertible use?+
Approved oil viscosity grades are SAE 0W-40, SAE 0W-30, SAE 5W-40, and SAE 5W-30 . If approved oils are not available, up to 1 US quart/liter of another oil meeting API SM quality standards or higher may be used . Always use BMW-approved oil to maintain engine health.
When should spark plugs be replaced?+
The recommended replacement interval is approximately 60,000 miles . The 2012 BMW 640i Convertible uses Bosch spark plugs as original equipment . Spark plugs should always be replaced in sets (the N55 engine uses 6 spark plugs) .
When should oxygen sensors be replaced?+
Oxygen sensors are scheduled for replacement at 120,000 miles, with a repeat service at 150,000 miles .
How often should brake fluid be changed?+
Brake fluid service is monitored by the CBS system and is a time-based service . If the battery has been disconnected, the service center should update the brake fluid service reminder . A conservative recommendation is to flush and replace brake fluid every 2 years.
What is Condition Based Service (CBS)?+
CBS is BMW's adaptive maintenance system that uses sensors and algorithms to calculate maintenance needs based on actual driving conditions, not fixed intervals . Service requirements can be displayed on the Control Display, and information is stored in the vehicle's remote key fob .
When should the serpentine belt be replaced?+
Belt manufacturers typically recommend belt replacement at 90,000 miles, with regular inspection for cracking, glazing, or squealing . The serpentine belt drives the alternator, water pump, and AC compressor .
How often should the transmission fluid be changed?+
Although BMW's official schedule may classify the transmission as "lifetime fill" under normal conditions, third-party references recommend periodic transmission fluid service for long-term reliability . For vehicles driven in severe conditions, more frequent service may be advisable. Consult your service center for guidance.
What should I do if my 2012 640i Convertible has been in storage?+
Storage periods during which the vehicle battery was disconnected are not taken into account by the CBS system . If this occurs, have a service center update the time-dependent maintenance procedures, such as checking brake fluid and, if necessary, changing the engine oil and the microfilter/activated-charcoal filter .
What is the oil capacity of the N55 engine?+
The oil capacity with filter is 6.5 liters . When performing an oil change, it is recommended to have approximately 7 liters on hand for the refill and future top-ups .