Interesting discussion on oil changes. Like Eddie I have had experience of oil analysis in the offshore industry. Substantial sums of money are saved by this approach. Oil sampling on gas turbines and large diesels running 24 hours a day 7 days a week are essential as they provide valuable metallurgical data determining which engine parts are starting to fail possibly leading to disaster (ie aircraft engines).
However, I have also heard of engine/oil development companies running engines for 100k +miles on the same oil and also running without oil - but these aren't stop/start scenarios in a cold/damp climate. The results are usually amazing.
But..........I would still rather change oil and filter annually irrespective of mileage rather than have to take it apart and inspect the bearings from time to time to convince myself all was well!
Several years ago I bought my '79 Plus 8 - 5000 miles on the clock, unknown servicing record - sump full of sludge, nuffsaid.........and I wouldn't trust a proprietary filter to last long term.
Repeating the obvious - oil/filter cheap - engine expensive! Change it yourself - cheap and simple - and all available at the push of a computer button, delivered to your door.
Simon
