Simon, in that case I need to offer you an apology.

On other threads I thought that you held the view that oil changes, like belt changes, only have to be carried out on mileage intervals with the maintenance schedule time limit ignored.
I am sorry if I am incorrect.

Good to hear that you now change your oil more frequently than the manufacturers' recommendation.

As a matter of interest, rather than the 12 month interval what have you reduced it to, 6 months?

Just to clarify John, I am not saying that the use of flushing oil is mandatory for a reliable engine, but it does help.
What you've made there John is an assumption, then convinced yourself that it's the truth without putting it to the test. I'd be interested to know why you didn't try flushing oil since the evidence suggests that it is beneficial, even with oil changes at half the recommended mileage (and that is exactly the point I am trying to make).
You are quite correct Bob. I know that you hold the opposite view and I am not seeking to change your mind, or anyone else's. However, I would like to be sure that I understand your belief correctly.

I said that, following an oil change sooner than the manufacturer's recommendation in terms of mileage, flushing oil removed contamination.
You argued that my oil was excessively contaminated because it had been in service for longer than twelve months, irrespective of mileage covered.
Do you therefore believe that if the engine isn't run at all for twelve months following an oil change, that the oil will then require changing again? If so, can you explain what you believe to be the technical reason for this?

Simon

What John describes is quite normal if flushing oil is never used, especially in diesels which produce more contamination than petrol engined cars.

Do you do your own oil changes David?

Simon