I think I know the answer but figure I’ll ask the braintrust of BITOG.
I recently purchased a 2003 BMW 330i ZHP with the M54B30 engine enhanced with ZHP cams from the factory. I bought it from the original owner who has been meticulous about maintenance. Despite the age, and 153K+ miles on the engine, the car drives like new as the original owner changed all fluids before they were due, and did preventative maintenance for common issues (bushings, cooling, DISA valve, VANOS, etc.). I have most receipts back to 2003.
The original owner first leased the car, then bought it from BMW Financial. Upon purchase the car shows oil changes every 7500-10,000 miles, some at BMW dealers, some at import specialists, and most by the original owner over the last 100,000 miles. That said, the first record of an oil change was at ~27,000 miles, but I assume it was done before that while leased.
I am about to do my first oil change on this car. It burns no oil, runs like a top, and there is no smoke. The last several changes have been with Castrol 5W40 European formula which used to meet BMW’s spec, but has since lost it despite no change in the oil formula.
My plan is to change the oil once it hits 5000 miles. I intend to use Castrol 5W40 European and a BMW filter. I am tempted to do a UOA to see if there’s any amiss.
Is there any merit in using something like BG EPR before the next change? I assume the frequent oil changes with quality synthetics has kept the engine pretty well free of sludge. No oil burning and smoke tells me that the ring lands are clean and the rings seat well.
Should I count my blessings and keep going as is, or should I use EPR to get out any crud?