N20 & N26 Servicing & Maintenance
Please take this advice as general in nature and choose what best works for you and your situation.
Performance Recommended Service Intervals
| Item | Interval |
|---|---|
| Engine Oil | 10,000 KM or 5,000 KM if using Ethanol Fuels regularly |
| Transmission (Auto) Oil | 80,000 KM |
| Transmission (Manual) Oil | 50,000 KM |
| Differential Fluid | 50,000 KM |
| Transfer Case Fluid | 50,000 KM |
| Spark Plugs | OEM Gap 50,000 KM, 0.022inch Gap 25,000 KM |
| Coil Packs | 60,000 KM |
| Injectors | 80,000 KM |
| Coolant | 85,000 KM |
| Brake Fluid | 50,000 KM |
| Brake Pads | 50,000 KM or When Indicator Lamp Is Active |
| Intake Filter | 50,000 KM |
| Cabin Filter | 30,000 KM |
| Accessories Belt | 100,000 KM |
| Fuel Filter (If Present) | 50,000 KM |
Preventative Maintenance & Common Failure Points
Timing Chain
Vehicles built on or before JAN 2015 should have their entire Timing Chain + Guides + Sprockets + Tensioner + Oil Pump Chain, Guides and Sprocket replaced before 120,000 KM or 80,000 Miles. Throughout 2015, the timing chain & oil pump drive system went through various changes.
Oil Pan Baffles
RWD N2x used in performance/street applications should look into having the sump updated to an Aluminium Pan + Baffle plate (URO sell the Aluminium Pan, Navardi Tuned sells baffle plates). The stock sump under high lateral turns and braking causes oil to move away from the pickup, causing irreversible engine damage from loss of oil pressure.
Turbo Feed Line
Vehicles built before SEP 2015 should have their turbo oil feed line updated. BMW introduced a check valve to stop oil from draining from the turbo and causing bearing damage.
Diverter Valve
Stock diverter valves are known to crack and leak under boost. Upgrade recommended.
Charge Pipes
Stock charge pipes are known to crack and leak under boost with age/heat-cycles. Upgrade recommended.
Turbo Inlet
Stock turbo inlets are known to crack. Consider upgrading to an aftermarket metal inlet.
Catch Cans
Oil catch can installation helps eliminate carbon/sludge build up within the cylinder head/intake valves and cleans the intake/charge air system from oil and contaminants.
Connecting Rods
Known to be weak in the N20/N26 but can be reliable as long as the tune does not target high torque especially below 4000 RPM or exceed 550 NM of torque at the crank.
Pistons
Cast pistons can be fragile in nature. It is important to ensure the tune does not run too lean as this causes piston rings to fail or pistons to crack.
HPFP
Pumps can fail at delivering correct amounts of fuel when tuned incorrectly or running exotic fuels such as ethanol that exceed flow capacity. When the pump fails to deliver flow demands, AFRs go lean causing piston/engine damage.
Cylinder Head Cracking
Mostly unknown issue stemming from the threaded seat of the spark plug in the combustion chamber. The sharp edges of the thin wall material exposed to combustion are the primary cause. The fix is to machine down the spark plug seat to remove the sharp edges and reduce stress concentration points. A spacer is only required if excessive material is removed during machining.
Recommended Engine Oils
Understanding Oil Weight Classifications
Multi-grade oils are rated with two numbers separated by a W (e.g. 5W-40). The W stands for Winter and refers to the oil's viscosity at cold temperatures.
- •First number (e.g. 0W, 5W, 10W) — The oil's cold temperature viscosity grade. Lower numbers mean the oil is thinner and flows more easily when cold. A 0W oil has lower viscosity at cold temperatures than a 10W, meaning it circulates faster through the engine on a cold morning.
- •Second number (e.g. 30, 40, 60) — The oil's viscosity at operating temperature (100°C). Higher numbers mean a thicker oil film at temperature, providing greater protection under load and at higher temperatures.
Example: A 5W-40 has the cold viscosity of a 5-weight oil, allowing it to flow and circulate quickly when cold, while maintaining the thickness of a 40-weight oil at 100°C. A 0W-30 would have even lower cold viscosity but a thinner oil film at operating temperature compared to a 40-weight.
BMW LL (Long Life) Oil Ratings
- LL-98: Older gasoline engines (1998)
- LL-01: High temp stability for gasoline (2001)
- LL-04: Gasoline & diesel with DPF (2004)
- LL-01 FE: Fuel economy variant of LL-01, uses lower viscosity for reduced friction
- LL-12/14/17 FE+: Fuel economy focused for newer engines
N2x engines are compatible with all LL ratings.
The oil weights below may not be 100% what you need if you have had an engine rebuild. Refer to your engine builder on what oil weight you should run based on your main and rod bearing clearances.
For Extreme Racing Applications
| Weight | Brand | Rating |
|---|---|---|
| 10W-60 | Shell Helix Ultra Racing | A3/B4, BMW M Approved |
| 10W-60 | Castrol EDGE Supercar | A3/B4, BMW M Approved |
| 10W-40 | Motul 300V Competition | A3/B4, Ester Core |
| 15W-50 | Red Line Racing Oil | A3/B4 |
| 10W-40 | Penrite 10 Tenths Racing 10 | A3/B4, LL-98 |
For Most Climates
| Weight | Brand | Rating |
|---|---|---|
| 5W-40 | Castrol EDGE | A3/B4, LL-01 |
| 5W-40 | LIQUI MOLY Pro-Engine M900 | A3/B4, LL-01 |
| 5W-40 | Mobil Super Synthetic Formula B | A3/B4, LL-01 |
| 5W-40 | MOTUL 8100 X-CESS GEN2 | A3/B4, LL-01 |
| 5W-40 | Pennzoil Platinum Euro | A3/B4, LL-01 |
| 5W-40 | Shell Helix Ultra | A3/B4, LL-01 |
| 5W-40 | Penrite HPR 5 | A3/B4, LL-01 |
For Very Cold Climates
| Weight | Brand | Rating |
|---|---|---|
| 0W-40 | Castrol Edge | A3/B4, LL-01 |