There has always been a good deal of discussion regarding oil changes...the frequency of the oil changes, the type of oil, etc. My son suggested that I have an analysis of the oil done and he recommended Blackstone Labs. I thought that you all would find the report intersting. I am not the engineer, he is, and he tells me that their conclusions are accurate, and that the Mobil 1, 5w30 is impressive. The info on the car is that it is a 2005 M6 with 11,200 miles. It is driven into the city everyday, in heavy traffic. I usually change the oil at 3000 miles, but have been busy, so this change is at 5000 miles, and will take their suggestion to keep it at 5000 miles. The oil filter is a Purolator Pure One.
The report comes with a good deal of statistical info, however, it is in PDF format, and I could not get it to post in format. Here is the conclusion. I find the comment about break in interesting. They had the mileage, so the implication seems to be that the engine is not completely broken in until about 20,000 miles.
EQUIPMENT MAKE: GM LS2
EQUIPMENT MODEL: 6.0L V-8
FUEL TYPE: Gasoline (Unleaded)
OIL USE INTERVAL: 5,000 Miles
OIL TYPE & GRADE: Mobil 1 5W/30 (Gas)
FRED: The high wear metals and silicon are not unusual finds in the oil from your new GTO. In fact, we would have been surprised if we didn't find them. The wear is high due to break-in of new parts, while silicon is from sealers and sand-casted parts. Universal averages show typical wear metals for an oil from this engine after 3,500 miles use. We expect your engine will look that good or better in two or three more oil changes. These 6.0L V-8's tend to wear very nicely, and yours should too once it's past wear-in. Stick with a 5,000 mile oil use until wear-in has past.