Mazda Skyactiv 2.2 D Engine noise, quick and precise diagnosis.

This engine failure is an extreme and rare case caused by negligence regarding oil changes and service intervals. (More about possible cause under main description)

A simple and precise diagnosis of engine noise can be applied to any brand of engine. In this instance, we are dealing with Skyactive 2.2 diesel engine knocking noise.

Link: Timing chain and oil pump chain (BALANCER UNIT) removal installation. Important info: you do not need to remove the sidewall (side cover) for the removal of the balancer unit. ( mark sprocket and oil pump chain, so you can align with the chain, later on, remove sprocket's bolt and remove the balancer unit) Mazda Skyactiv D engines Timing chain...


Another Link: Balancer Unit removal and Strainer replacement: P06DE P055F Low Oil Pressure Mazda 2....

In this case, I suspect there was an injector gas leak causing carbon build-up and gather on the oil pump filter( its proper name is Strainer), So the Strainer gets clogged and inhibits lubrication.
To prevent lubrication failures, Mazda introduced software to monitor oil pressure constantly, and if the oil pressure drops below a particular threshold, a warning light gets triggered. At this stage, it is not harmful to the engine. What is dangerous is the negligence of the driver. (often, the vehicle comes for inspection after hundreds of kilometers since the initial malfunction). For the Mazda workshop, it is easy to check at what mileage DTC had been set, available only for dealers.

Prevention: in the case of a warning light, go to the dealer right away, do not delete error codes; it will give the technician a clearer picture.

Prevention with no issue: ask for replacing injector gaskets every 100 thousand km. Cost is incomparably low to the price of any related repair.

Another essential factor is proper engine oil. Other oils not approved by
the manufacturer will not withstand oil dilution, so use genuine oil:
Engine oil for (Europe) Mazda Original Oil Supra DPF 0W-30, Mazda Original Oil Ultra DPF 5W-30, Alternative ACEA C3 0W-30, 5W-30.
Engine oil (Except Europe): Viscosity (SAE) 0W-30, 5W-30 Grade ACEA C3
Australia and New Zealand: Viscosity (SAE) 5W-30 Grade ACEA C1 or JASO DL-1

Regarding wrong oil and not performing an oil change is common practice (oil gets diluted with diesel and the lubrication gets significantly worse, especially at the end of its life). Oil life is dependent on your driving habits and driving distances. If you drive short distances daily, the automatic  DPF  regeneration is performed more often, so oil increases dilution. That is why Mazda has introduced flexible service and oil change. PCM (Powertrain Control Module) software can monitor driving distances, frequency of DPF regeneration, and other factors contributing to faster deterioration of engine oil and depending on gathered data to inform you when oil change is needed.