Quote:
Originally Posted by Elk
It is the same on motorcycle forums as well; types of oil and when to change it is an endless source of argument.
It may be because, with modern oils, it really does not matter what you do within reason. Thus, everyone is right.
|
WRONG.
The myth that will not die. Changing oil frequently can't hurt.
Actually a number of studies show that oil in service ("aged oil" as one SAE paper calls it) does a BETTER job of lubricating than fresh, green oil.
http://papers.sae.org/2007-01-4133/. A similar study reported in SAE (don't have a bookmark) came to same conclusion - - showed that fresh oil dissolved tribological layer of antiwear adds (zddp) laid down by nasty old aged oil before building up its own antiwear layer. As if that's not enough, a lubricants engineer with decades of experience with Castrol and Mobil not long ago says he's seen data indicating changing oil too frequently on direct injection turbo motors (are you paying attention N54/N55 owners) builds deposits faster!
And BMW has a nifty Bosch-made oil condition sensor in the sump that measures the electrical conductivity of the oil - - the conductivity changes as the oil builds wear metals, oxidizes, loses or gains viscosity, builds fuel dilution, builds acids, etc. It's not going to let you run your run your oil to extinction.
All for nought. We know better.
The article mentioned above, showing a sludged engine, is from La Jolla Independent, an indie shop not a BMW dealer. They specialize in restoring older BMW's. They have no training I know of in tribology or lubricants engineering.
For every anecdote there is an anti-anecdote -
http://www.bobistheoilguy.com/forums...64#Post1196764
http://www.bobistheoilguy.com/forums...143203&fpart=1