My 3.6 has had an oil flush nearly every service (10k km). The motor has always had this subtle intermittent or inconsistent rattle on idle and acceleration. The motor is otherwise smooth and quiet. I assumed it was just a normal operating noise.

I recently did an oil flush using the Cost Effective Maintenance flush. Since the engine rattle noise has gone. The oil dipstick is also staying very clean since the flush.

Anyone have any theory on the effect of the flush and what the noise was?

Iím wondering if the turbo has been starved of oil and the noise was the turbo fan hitting the housing, and the oil flush has cleared a blockage which has resolved the oil starvation issue. So no more noise. The noise was more on the driver side which seems to be the more at risk turbo.