2000 — 2005
3.5L 6G74 V6 (FWD)
Petrol
Check this by shifting into reverse and drive while stopped on a flat surface; if there is a noticeable clunk or a delay before engagement, the F4A51 automatic transmission may be showing its age.
While driving at a steady 80-100km/h, listen closely for a rhythmic 'thrumming' or vibration, which can sometimes indicate the center support bearing or inner CV joints are starting to wear.
During your static check, observe the cooling fan operation; if the car runs warm at idle but cools down once moving, the radiator may be partially clogged, a common occurrence in 6G74 engines of this vintage.
Check this by turning the steering wheel lock-to-lock while stationary; any whining noises or jerky feedback could suggest the power steering pump or rack is beginning to reach the end of its service life.
Usually marks the second or third timing belt interval; verify if the water pump and tensioner were replaced alongside it.
Often the point where engine mounts begin to show signs of perishing, leading to increased cabin vibration.
Consider checking suspension bushings and ball joints, as these components frequently require refreshing to maintain the Diamante's smooth ride quality.
Check the coolant color; ensure it is a clean, bright green or pink rather than a murky brown or orange sludge.
Confirm the timing belt has been replaced recently, as the 6G74 is an interference engine and this is crucial for its longevity.
Inspect the transmission fluid via the dipstick; it should ideally be a translucent red color, not dark brown or smelling like burnt toast.
Examine the CV boots for any signs of splitting or grease spray, as these are common wear items on high-mileage front-wheel-drive sedans.
Test all electronic accessories, specifically the climate control displays and electric window regulators, as these can occasionally act up with age.
Estimated repair costs if issues arise
Because this engine relies on a belt, it is vital to keep up with the service interval. If this hasn't been done recently, you should consider setting aside funds to have a professional technician handle the replacement to protect the engine internals.
As these cars age, the rubber bushings in the suspension arms can crack, leading to a vague steering feel. Depending on the car's history, you might eventually need to budget for a partial or full bushing kit replacement to restore that smooth handling.
If you notice firm shifts, you might eventually need to budget for a transmission fluid flush or a valve body service. If this component needs attention in the future, it is wise to consult a transmission specialist early to avoid more complex issues.
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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