Quote Originally Posted by kelvo View Post
Every day's a school day

Oils can come in all sorts of pretty shades.

Old Castrol Transmax Z ATF was green (I still have a bit over 1l, use it in the power steering. It's the same shade as the Texaco PAS14315 used as the OE fluid), Royal Purple is, you guessed it, purple. Some of Lubrication Engineers oils are green, etc.

One Triboligist I've spoken to years ago (the chemist/engineers that actually design and blend the fluids) told me that the dye is the most expensive component per litre !
There's just so little used in a drum of oil.