Yes, GM has now made that standard to meet the minimum requirements for blended oils. This is the reason they have created DEXOS.
The last time i checked, it does
The General Motors oil specification in question, GM6094M, denotes specific loads and temperatures to be met in the test lab.Independent research has not uncovered the specific goals of GM6094M, but quickly showed that many synthetic and mineral based oils meet the requirements, so there is nothing too exotic about this engine oil requirements. Both Havoline (mineral) and Redline (synthetic) 5W-30 oils meet this specification, for example, so a number of oils should work. From an older post on GM TechLink website, here is a list of oils that met this spec (circa 2005): http://forums.genvibe.com/zerofile/7142/synthgd.pdf
In order to ensure if you can mix these two syn oil, you should carefully check the base of each oil (cross check the oil formular). If you find they have same oil-base, you can mix it
You can mix part synthetic oil with full synthetic oil.
Semi synthetic or synthetic blend is a combination of synthetic and conventional oil. Full synthetic oil is just that 100% synthetic oil.
5W/30 synthetic oil is best, conventional petroleum base motor oil is acceptable but inferior, Brand does not matter with full synthetic, but beware, many are blends
Oil that comes out of the ground is not synthetic but is called crude oil. Synthetic oil is man made with synthetic compounds. They are both oil.
3000 miles if using regular oil, 6000 if using synthetic. I use synthetic for my RSX-S, but regular would do for a base model.
Synthetic oil manufacturers.
Yes, Synthetic oil is synthetic oil no matter who makes it.
Yes, that is what a synthetic blend is that they sell.
It is a combination of synthetic oil and conventional oil.