In Reply to: Depends what you're looking for... posted by MikeW on September 21, 1999 at 12:55:01:
You sort of prove my point...if all new bimmer owners get into the habit of changing their oils at 15k intervals when the car is new. They will continue to do so when the car gets old and this is where the problem lies-old engines letting in tons of contaminants destroying the engine.
I also must state that oil breaking down is an old wives' tale....consider the fact that the oil was under the earth for MILLIONS of years under more heat and pressure than your engine can ever dream of producing...the reason we change oil is because it gets dirty and that's all. Although companies like to scare us with this 'viscosity break down' nonsense then take the supposedly 'broken down' oil and fix it?? Nope they merely refine and clean it up.
But hey Castrol and Mobil got to sell their products right?
: The question here is how the oil holds up over a given period of time, not how the engine is holding up (although oil analysis is quite useful for that also). In an older engine, the oil wouldn't break down any faster, it just might pick up more contaminents through the greater clearances of the worn in engine. The info we seem to be getting here is that the oil is still servicable at 11K miles.
: : Would it not be more beneficial to have the oil tested on e36 or older car (thus simulating what an e46 analysis will predict a couple years down the road)
: : I ask because I would not expect much deterioration to be found in a brand new engine....it's after a couple years when seams stretch and things get loose that one can determine if frequent oil changes are truly required.............Great post though
: : I had my oil analized last week and just got the results back.
: : : 1999 E46 328i 28,000 miles on the odometer
: : : 11,000 miles since last oil change with BMW synthetic 5W40
: : : (approx 50/50 highway/city)
: : : The reports states that the oil still falls within the spec'ed viscosity range (5W40)
: : : no trace of fuel, water, or antifreeze in oil.
: : : and traces of metals (aluminum, iron, copper and about 4 other types of metal) were all virtually non-existant.
: : : traces of silica (dirt) are also very minimal. (using K&N air filter) (there was a side note that said air filter is
: : : working properly)
: : : The conclusion of the report was that the oil is suitable for continued use and engine is in excellent condition.
: : : I think BMW engineers know what they're doing, and it'll be safe to go 15k to 18k before changing the oil.
: : : When it hits 18k, I'll send the oil in to be analized again and will post the results.
: : : Jack