Overcharged

I gave B's Focus an oil change last week - it was well overdue - and took the old oil down to the recycling place today. I was surprised to find well over 5 litres of oil drained out of the sump when the nominal capacity is 3.8 litres. It turns out that when these engines regenerate the DPF they use (not burn obviously - B's 1.6 is doing about 33 to the gallon at the moment) excess fuel and quite a bit of it gets past the rings/valve guides and into the engine oil. So there's me thinking the engine doesn't use much oil when in reality it's getting replenished with bloody diesel. I hate to think what the lubricating properties of the stuff I drained out were. I've since read accounts where the oil eventually thins so much it gets back up past the rings and the engine runs on that in an unstoppable manner until it destroys itself. I did buy a new DPF (yet to be fitted) but I've changed my mind - the old DPF is being cut out next week and is not getting replaced. They are bloody awful things and about as environmentally sound as a concrete cattle pen.