can you use 10W-30 synthetic oil in a 2004 BMW X3
Yes you can. Check out this site to see which weight oil is best for your engine. http://www.bobistheoilguy.com/motor-oil-101/
In deed. Castrol is recommended, but Royal Purple and AmSoil are pretty darned good in my book.
By using a different weight oil then BMW recommends your could start consuming more oil then if you used 5w30.
Looking for a Used X3 in your area?
CarGurus has 12,111 nationwide X3 listings starting at $3,749.
Search BMW X3 Questions
BMW X3 Experts