acea c3/c4 are stay in grade high performance fully synthetic oils for petrol and diesel engines with diesel particulate filters and Three way catalyst systems. These oils will extend the life of thw DPF and the Catalytic converter.

So is this why dealers are not putting in the correct grades, so that further down the line we will have no warranty claim if we don't notice the "wrong" type or gade of oil is in the engine, and then we have to pay for a very expensive DPF filter at our own expense.

Am I being too cynical or what?