From what I'm seeing here, extended oil change intervals are done to reduce the time and cost of maintenance on a vehicle but we don't have enough information on the long term consequences for those that keep their vehicles beyond the warranty. The examples here might be from people that really care for their vehicles but that does not represent the majority.
A UOA is telling us about the oil but there's still the question about the actual condition of the engine.
Since most people don't keep cars that long the longer OCI makes sense. When there's doubt you just trade.
What prompted me to ask was what I saw today. A BMW that ran dealer oil and religiously followed the BMW intervals. A couple of UOA's look good, no problems noted. At 200K the engine is junk. It just barley failed the California smog test. It looks pretty clean inside, no sludge but the crank has egg shaped journals, compression rings perfect, oil control rings failing, the camshafts are gone and so are a lot of the other bits and pieces that would really run up the overhaul bill. In simple terms, this engine is not a candidate for a rebuild. It was economical to maintain but not to rebuild. So the owner got a vehicle that was not expensive to maintain. If the second owner would have received this vehicle without the tear down the ownership might have been expensive. The car is being parted out.
So it appears that the extended OCI's achieved their purpose.
A UOA is telling us about the oil but there's still the question about the actual condition of the engine.
Since most people don't keep cars that long the longer OCI makes sense. When there's doubt you just trade.
What prompted me to ask was what I saw today. A BMW that ran dealer oil and religiously followed the BMW intervals. A couple of UOA's look good, no problems noted. At 200K the engine is junk. It just barley failed the California smog test. It looks pretty clean inside, no sludge but the crank has egg shaped journals, compression rings perfect, oil control rings failing, the camshafts are gone and so are a lot of the other bits and pieces that would really run up the overhaul bill. In simple terms, this engine is not a candidate for a rebuild. It was economical to maintain but not to rebuild. So the owner got a vehicle that was not expensive to maintain. If the second owner would have received this vehicle without the tear down the ownership might have been expensive. The car is being parted out.
So it appears that the extended OCI's achieved their purpose.