Quote:
Originally Posted by NVHoo
Consumer Reports and other organizations have shown that changing oil more frequently than recommended in the owner's manual is unnecessary as long as you use the manufacturer's oil spec. The concept of changing oil more frequently is a holdover from the ancient days of old oil technology. I've been following this rule for the past 30 years, and various turbos for the past 20, in a variety of cars in my family and have never had an internal failure. You can also ignore the "severe" recommendations for cars that have that caveat. When BMW and Audi began to offer free maintenance here in Vegas they initially changed oil more frequently but the factory quickly told them it was unnecessary, even in this desert heat.
The arguments I hear for changing more often is "it can't hurt" and/or "it does not cost much so do it more frequently" but all your doing is wasting money and a natural resource.
Tracking the car might change that recommendation, depending on how often and what the track experience is. For example, if you are a once a year wonder at a weekend high performance driving school, I would not sweat it.
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This truly applies to the 128i with it's port injected normally aspirated design. If you a CERTIFIED LL-01 oil it is waste to change every 3K miles, and probably 5K is also a waste. If I was a mellow driver and topped it off regularly, you might even be able to go 12K miles on good oil in normal highway driving
But what ends up happening in the real world is that these cars consume some oil and with these long 2 year intervals never check their oil so they spend months driving around with 6 quarts instead of 7 which affects how much wear happens on the oil. If you change it regularly, you tend to be safer because you replace it while it's only down 1/2 a quart and at hafl the interval.
So it totally makes sense if you are on top of checking your oil regularly and using good filters that will not get brittle and disintegrate after two years.
But the turbo motors are a different story. They essentially were delivered with the same 5W-30 oil of the non turbos despite higher thermal loads and direct injection where raw fuel makes it onto the cylinder walls and mixes with the oil. Eventually, this starts to weaken the oil so now you can gamble that will be providing full protection on that summer canyon run. Once you understand what the same oil is being subjected too, 12-15K miles almost seem out of the question in a DI Turbo car. I use the 7500 mile/1 year guideline on my turbo but it is actually more like 3000 miles because I only put that much on my 1M in a year.
So you raised a great point but I'm sure even consumer reports said MOST of the time it is a waste. There are some times it makes sense and understanding your motor is vital. Most LL-01 oils are built to survive direct injected turbo motors, which means that you 128i guys have it easy!