2018 maintenance schedule
2018 BMW 440i Convertible Complete Service & Maintenance Schedule
The 2018 BMW 440i Convertible does not follow a traditional fixed-mileage maintenance schedule.
Last updated
November 5, 2026
Reviewed for service schedule clarity.
Key Takeaways
- Factory Maintenance Schedule: OEM documentation specifies a 30,000-mile interval for brake fluid, an engine air filter at 36,000 miles, spark plugs at 100,000 miles, and automatic transmission fluid at 100,000 miles . Both the convertible and Gran Coupe models share the same engine and service intervals.
- Engine & Oil: The 2018 440i Convertible is powered by the B58 3.0-liter inline-six engine. BMW recommends 0W-20 (LL-17 FE+) engine oil, which has a low-ash formula compatible with the catalytic converter .
- Oil Change Guidance: While BMW's CBS system suggests intervals around 10,000 miles, many independent specialists recommend an oil change every 5,000 miles for optimal engine health .
- Warranty: The vehicle originally included a 4-year/50,000-mile basic warranty and a 3-year/36,000-mile maintenance program .
- Maintenance Costs: Year 5 is the highest-cost year for maintenance, estimated at approximately $2,861 .
Understanding BMW's Condition Based Service (CBS) System
The 2018 BMW 440i Convertible does not follow a traditional fixed-mileage maintenance schedule. Instead, it uses BMW's Condition Based Service (CBS) system, which monitors driving style and conditions to calculate when service is actually needed. The system tracks multiple service items separately, including engine oil, front and rear brake pads, brake fluid, and vehicle checks. Service notifications appear on the Control Display when maintenance is due. Service data is stored on your remote control key and can be read by your BMW Service Advisor.
BMW recommends that maintenance and repair work be performed by an authorized BMW service center or a workshop with trained personnel who follow BMW specifications.
Factory Maintenance Schedule (OEM)
Based on OEM documentation for the 2018 BMW 440i, the following service intervals are specified :
| Distance (miles) | Action | Item |
|---|---|---|
| 30,000 | Flush/replace | Brake fluid |
| 36,000 | Replace | Engine air filter |
| 60,000 | Flush/replace | Brake fluid |
| 72,000 | Replace | Engine air filter |
| 90,000 | Flush/replace | Brake fluid |
| 100,000 | Replace | Spark plugs (6 required) |
| 100,000 | Change | Automatic transmission fluid (3.2 units) |
| 108,000 | Replace | Engine air filter |
| 120,000 | Flush/replace | Brake fluid |
| 120,000 | Replace | Oxygen sensor |
| 144,000 | Replace | Engine air filter |
| 150,000 | Flush/replace | Brake fluid |
| 200,000 | Replace | Spark plugs |
| 240,000 | Replace | Oxygen sensor |
| 300,000 | Replace | Spark plugs |
Engine Oil & Filter Service
BMW Factory Schedule
BMW's CBS system determines the precise oil change interval based on driving style and conditions. The system typically cycles every 10,000 miles, but this varies based on actual driving conditions.
Oil Specifications
The 2018 BMW 440i Convertible is powered by the B58 3.0-liter inline-six engine .
Oil Approvals: BMW has multiple Longlife oil specifications. The LL-01 formula covers almost all of BMW's gasoline-burning engines, while LL-22 FE++ is specified for later Gen 3 B58/B48 engines with mild-hybrid technology .
The 2018 440i is compatible with the following BMW Longlife-approved oils :
- BMW LL-17 FE+ – 0W-20 oil recommended for B58 engines
- BMW LL-01 – Suitable for 5W-30 and 5W-40 viscosities (ACEA A3/B4, API SN/CF)
- BMW LL-22 FE++ – Meets ACEA A5/B5, API SN standards
Oil Capacity: Approximately 6.5 liters with filter .
BimmerWorld recommends 0W-20 (LL-17 FE+) for the B58 engine. This oil has a low ash content compatible with modern catalytic converters and reduces drag and friction for improved fuel economy. "FE" stands for Fuel Efficient .
Owner Guidance
Motor oil is the single most important element in keeping your engine healthy. Many independent specialists recommend a more conservative oil change interval for long-term engine health:
- Standard approach: Follow the CBS system (approximately 10,000 miles or 1 year)
- Conservative approach: 5,000 miles, especially for aggressive or city driving, frequent short trips, or hot climates
For owners who drive their vehicle spiritedly, BimmerWorld recommends Red Line Oil as an alternative for track or performance use .
Estimated Cost: An oil change service for the B58 engine using an oil change kit (7 liters of oil, filter, drain plug washer) is available for the 2018 440i .
Brake Fluid Service
BMW Factory Schedule
OEM documentation specifies brake fluid flush and replacement at 30,000, 60,000, 90,000, 120,000, 150,000-mile intervals . BMW also recommends changing brake fluid every 2 years as a time-based service .
Brake Fluid Inspection
A brake fluid inspection for the 2018 BMW 440i is estimated at approximately $114.99 . If the brake fluid appears black or brown, it is past due for service .
Why Brake Fluid Darkens: Brake fluid darkens due to:
- Normal aging gone unchecked (fluid not changed regularly)
- Moisture contamination from rubber brake lines
- Deteriorating rubber lines
- Normal heating of brake fluid at the calipers
Signs Brake Fluid Needs Service:
- Brake fluid appears black or brown
- Brake pedal feels spongy
- Diminished brake system performance
Fluid Options:
- Prestone DOT 4 Brake Fluid: Synthetic high-grade fluid, 50,000-mile fluid life
- Prestone MAX DOT 4: Highest grade, 75,000-mile fluid life
- Pentosin DOT 4 LV: Low-viscosity formula ideal for modern ESP and ABS systems
Estimated Cost: A brake system flush for the 2018 BMW 440i is estimated at approximately $234.87, with dealer prices ranging from $258.95 to $327.00 .
Spark Plug Service
BMW Factory Schedule
OEM documentation specifies spark plug replacement at 100,000 miles, with a second replacement at 200,000 miles and a third at 300,000 miles . The vehicle requires 6 spark plugs for the 6-cylinder B58 engine.
Why Spark Plug Service Matters
Weak ignition coils or worn spark plugs cause misfires, rough idle, hard starts, and poor mileage. New coils and plugs restore crisp throttle response and cleaner emissions .
Even if only one spark plug is found to be faulty, they should always be replaced in sets. The B58 engine requires six spark plugs.
Estimated Cost: Spark plug replacement for the 2018 BMW 440i L6-3.0L Turbo is estimated at approximately $613.10, with dealer prices ranging from $699.59 to $943.67 .
Engine Air Filter Service
BMW Factory Schedule
OEM documentation specifies engine air filter replacement at 36,000, 72,000, 108,000, 144,000, 180,000, 216,000, 252,000, and 288,000-mile intervals . The engine air filter filters incoming air fed to the engine.
Oxygen Sensor Service
BMW specifies oxygen sensor replacement at 120,000 miles, with a second replacement at 240,000 miles .
Automatic Transmission Fluid Service
BMW Factory Schedule
OEM documentation specifies changing the automatic transmission fluid at 100,000 miles . The automatic transmission fluid is used for lubricating and cooling the automatic transmission. The specified amount is 3.2 units.
Maintenance Cost Overview
Based on data for the 2018 BMW 440i Convertible, estimated maintenance costs by year are approximately :
| Year | Estimated Cost |
|---|---|
| Year 1 | $0 |
| Year 2 | $78 |
| Year 3 | $258 |
| Year 4 | $146 |
| Year 5 | $2,861 |
*Costs are estimates and vary significantly by region and service provider. The 3-year/36,000-mile maintenance program covers scheduled maintenance during that period .*
Frequently Asked Questions
1. How often should I change the oil in my 2018 BMW 440i Convertible?
BMW's CBS system determines the interval based on your driving style, typically cycling every 10,000 miles or 12 months. Many independent specialists recommend a more conservative 5,000-mile interval for optimal engine health . The B58 engine has an oil capacity of approximately 6.5 liters with filter.
2. What oil does the 2018 BMW 440i Convertible require?
The B58 engine requires BMW Longlife-approved synthetic oil. BMW 0W-20 (LL-17 FE+) is the recommended oil with low ash content for compatibility with catalytic converters . BMW LL-01 (5W-30/5W-40) is also suitable. Refer to your owner's manual for the correct viscosity for your climate.
3. When should the brake fluid be replaced?
OEM documentation specifies brake fluid flush and replacement at 30,000, 60,000, 90,000, and 120,000-mile intervals . If the brake fluid appears black or brown, it is past due for service . A brake system flush for the 2018 BMW 440i is estimated at approximately $234.87–$327.00 .
4. When should the spark plugs be replaced?
OEM documentation specifies spark plug replacement at 100,000 miles, with a second replacement at 200,000 miles and a third at 300,000 miles . The B58 engine requires 6 spark plugs. Replacement is estimated at approximately $613.10–$943.67 .
5. When should the transmission fluid be changed?
OEM documentation specifies automatic transmission fluid change at 100,000 miles . The specified amount is 3.2 units.
6. When should the engine air filter be replaced?
OEM documentation specifies engine air filter replacement at 36,000, 72, 000, 108,000, 144,000, 180,000, 216,000, 252,000, and 288,000-mile intervals .
7. When should the oxygen sensor be replaced?
OEM documentation specifies oxygen sensor replacement at 120,000 miles, with a second replacement at 240,000 miles .
8. What warranty coverage did the 2018 BMW 440i Convertible include?
The vehicle originally included a 4-year/50,000-mile basic and powertrain warranty, 144-month/unlimited-mile corrosion perforation warranty, 48-month/unlimited-mile roadside assistance, and a 3-year/36,000-mile maintenance program . This period has expired for all 2018 models.
9. How much does a brake fluid inspection cost for the 2018 BMW 440i?
A brake fluid inspection for the 2018 BMW 440i xDrive is estimated at approximately $114.99 .
10. Is the 2018 BMW 440i Convertible expensive to maintain?
Maintenance costs are typical for premium German sports cars. Year 5 is estimated at $2,861, while years 1-2 were covered under the original maintenance program . Regular preventative maintenance is essential for avoiding more costly repairs.
*Always consult your vehicle's owner's manual and the CBS system for the most accurate maintenance requirements for your specific 2018 BMW 440i Convertible. Maintenance needs may vary by production date and driving conditions.*