Good info !!I mainly wanted something that would respond well after a -40F/12 hour cold soak which is not uncommon. The diesels I have would labor and sound like they were initially running without pressure with the factory fill Castrol, this was corroborated by the low pressure lamp on the dash. I switched to Red Line and there was a world of difference. Faster cranking and no strange engine noises, almost immediate pressure. Ravenol was also good. Mobil 1 was better than the Castrol but not as good as the Red Line/Ravenol using the above non-scientific paramaters. The Valvoline sounds almost as good as the boutiques. I am now retired so the 12 hour cold soaks are a thing of the past. The Valvoline is 40% cheaper than the Red Line and 50% cheaper than the Ravenol. I can't really justify the cost anymore. I didn't try Amsoil as I don't support quasi MLM products.
I agree