2000 — 2005
3.5L 6G74 V6 (AWD)
Petrol
While accelerating steadily from a stop, monitor the transmission for any hesitation or flared shifts; in high-mileage examples, the INVECS-II transmission may eventually show signs of solenoid wear.
Turning the steering wheel fully to both locks while stationary to listen for any whine or groaning from the power steering pump, as these units can become sensitive to fluid degradation over time.
Navigate over a series of small bumps and listen for clunks from the front suspension; it is common for the control arm bushings to show signs of age on the second-generation Diamante due to the vehicle's weight.
Check the dashboard cluster for missing pixels or lighting issues, as the electronics of this era are known to experience minor intermittent glitches that become more noticeable with prolonged sun exposure.
Usually marks a time to inspect the cooling system components, specifically the radiator hoses and thermostat, which may become brittle.
A common interval to check the integrity of the AWD transfer case seals and ensure the CV joints are free of torn boots.
A good time to review the alternator and starter motor health, as these are reaching the end of their design lifespan in many 6G74 engines.
Ensure the timing belt and water pump have been replaced according to the manufacturer's schedule, as this is vital for the 6G74 engine's longevity.
Check that the automatic transmission fluid is clean and pink-tinted rather than brown or burnt smelling.
Regularly clean the Mass Air Flow (MAF) sensor, as these can accumulate dust and affect the smoothness of the V6 idle.
Inspect the underbody for any surface corrosion, especially around the rear subframe mounts, which is a common area to monitor in coastal New Zealand regions.
Verify that the cooling system has been bled properly to prevent air pockets, as these engines appreciate a stable operating temperature.
Estimated repair costs if issues arise
Because this engine is an interference design, keeping up with the belt change is essential. If the service history is missing, you might eventually need to budget for this replacement to ensure long-term peace of mind.
If the ride feels a bit loose or 'floaty' compared to when it was new, you might eventually need to budget for refreshing the front control arm bushings to restore that classic Diamante comfort.
To keep the INVECS-II shifting smoothly, it is wise to plan for a transmission fluid flush. Depending on the car's current driving behavior, this is a proactive step that helps avoid future complications.
Noticed something inaccurate or missing?Suggest an edit→
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