so, did an oil change on my truck today, picked up some castrol edge fully synthetic, and completed the change.
Afterwards, a friend of mine told me he is an amsoil dealer, and will sell me the oil and such at his cost. In talking with him, he mentioned that they have 3 tiers, the top tier being good for 48,000kms and the mid-tier being good for 20,000kms.
I am wondering though, while the extended life is appealing, how do manufacturers view them? If you put oil good for 48kms, are the dealers ok with that kind of interval? does it void warranty?
Also, are these oils worth it? do they provide any real benefits or is it marketing?