2011 — 2017
3.0L N55B30 Inline-6 - 640i (Note: 630i badge was skipped for this generation in NZ markets, replaced by 640i)
Petrol
Check the N55 engine startup | Detail: While the car is cold, listen for any metallic rattling from the engine bay. It is helpful to note if there are any signs of VANOS solenoid sticking or timing chain noise, which can sometimes occur as these engines age.
Inspect the electronic parking brake (EPB) | Detail: When parking, engage and disengage the brake several times. In models of this age, it is worth checking for any error codes or sluggishness, as the electronic actuators can occasionally require attention.
Evaluate the transmission smoothness | Detail: During low-speed acceleration, monitor the gear shifts. If the shifts feel hesitant or clunky, it may be a good idea to inquire if the transmission fluid and mechatronics seal have been serviced, as this can affect long-term drivability.
Observe the iDrive and infotainment functionality | Detail: Cycle through the menus and test the Bluetooth and GPS. These systems can sometimes show their age, so verifying the responsiveness of the controller knob and the display screen is a wise step.
Consider a proactive check of the water pump and thermostat, as these cooling components may reach their typical end-of-service life around this time.
This is a great time to inspect the condition of the suspension bushings and control arms to ensure the BMW's signature driving dynamics remain sharp.
A deep inspection of the turbocharger vacuum lines and gaskets is recommended to ensure the N55 engine continues to provide smooth power delivery.
Prioritize regular engine oil changes every 10,000km to keep the N55's turbo and VANOS system happy.
Check the condition of the cabin air filters to ensure the climate control system remains efficient and the interior stays fresh.
Inspect the run-flat tires for even wear, as the 6 Series geometry can be sensitive to alignment issues.
Ensure the engine air filter is replaced on schedule, as a clean intake is vital for turbo longevity.
Keep an eye on the brake pad wear sensors, as they are a reliable way to monitor your stopping power needs.
Estimated repair costs if issues arise
In the N55 engine, the water pump is electric and can occasionally fail without warning. If this component needs attention in the future, the estimated cost in NZ is usually reflective of a specialized cooling system overhaul.
It is quite common for the valve cover gasket to become brittle over time, potentially leading to small oil seeps. Depending on the car's history, you might eventually need to budget for a replacement to keep the engine bay clean.
Because the N55 uses direct injection, carbon buildup can accumulate on the intake valves over many kilometers. Periodic walnut blasting is an effective way to restore engine performance.
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Disclaimer: This report is generated with the assistance of AI analysis based on verified automotive data. While we strive for 100% accuracy, enthusiasts should always conduct physical inspections and consult service records. View Full Disclaimer