Comments from a reader regarding oils and the use of oils in certain vehicles.
I have just been reading your article on oils. I have spent many years researching oils on a personal basis both for motorbikes and for cars. Oils used in motorbikes are far more critical than cars but there are commonalities.
Whilst I basically agree with your article there is one area that you need to provide more clarity and that is around manufacturers own oil designations. I'll use VAG as I have some experience of their vehicles.
Sometimes an oil is upgraded for a particular vehicle and then you get the superseded by, etc. However with VAG group they have specific instruction what oil to use and not to use. For instance in diesel PD(Pumpe Duse) engines there are only two oils that you can use, one for set intervals and the other for long life. No other oil spec is acceptable. The earlier 1.9TDi engine(non DPF) had to use a specific oil and still does, even though there are later oils. (In fact VAG themselves state that the oil should be 5W40 whereas most oil suppliers want to specify for that engine 5W30.) And if you have a DPF then the oil is different again. The oil has been varied dependant on the requirement of the specific type of engine and sometimes it is a compromise particularly when the environment gets involved. In fact some oil brands will specify that the oil meets specific VAG specification but then goes on to say not to be used in specific engines which is a bit silly as it was originally designated for that type of engine.
I know that some other car manufacturers are similar so I do think that it
is made clear in these type of published date as less knowledgable may end up
putting the wrong oil in the vehicle while thinking that the oil specification
has been superseded.
This will apply to other makes as well.
Mr G Goode