To follow-on WRT the 3.8 engine noise during initial start-up, I'm glad to hear the 10-30 Mobil-1 made a good improvement to the mileage and noise level to the engine. I more inclined to think, it may be the lifters that is causing the noise, but if goes away after two seconds, I wouldn't worry about it. That is normal for some engines.
As I posted, I only have over 500 miles to my Genesis and upon looking at the oil level using the
dipstick, I can tell that there are minute metal particles in the oil. It's easy to tell, when you wipe off the oil in the
dipstick with a clean light colored paper towel, (this is for new or rebuilt engines), you can see the towel have a somewhat black shade, as opposed to darker shade of color from you original oil. It is an indication of metal in the oil. this is normal as each new internal components are "mating or fitting " with each other.
Background: I worked on fighter aircraft and we do engine oil and hydraulic analysis a lot, so I know what to look for, granted we used special equipment to further analyze oil samples. For the record I haven't used our equipment to analyze my own engine oil. But if anyone is interested, there are companies out there who, for a fee, will analyze your oil. That may be extreme.
I also rebuild engines as a hobby, and this initial black oil color is a normal for an engine that is being "broken-in" but left on the engine at the recommended 7500 miles "may" and IMO can cause a long term effect to the internal parts. Perhaps the Hyundai OEM oil filter is of a very high quality designed to last that long. I have seen other Hyundai Forums that had compared other oil filters against
aftermarket brand and they are saying Hyundai OEM oil filter is far better than
aftermarket.
IMHO, and personally, I plan to change my Genesis oil at 1000K miles using conventional and OEM oil filter to get rid of the metal particles caused by the initial break-in, then to full Synthetic at 3000. I will document the replacement of the oil and OEM filter at 3000k Miles for warranty purposes. Then I'll go from there. People may think this is beyond normal, but I am relying heavily from my experience in Aviation in preventive maintenance.
Thanks for all the info, and I hope this help anyone in some ways.