(I know there's a thread around here somewhere but couldn't find it.) My question is, is there anything wrong using zinc-free for older machines that don't require it? I only have one bulk tank so it has the zinc-free
I think the thread was a problem of not knowing where zinc-in-the-oil was coming from. If the zinc-free oil has the same 'rating', I can't see that there is a problem. I.e. AW oil without zinc is AW oil... (that is, if 'TO-4' satisfies the requirement, it does so without regard to what is in the additives in the oil.)