Did an oil change the other day. The oil has a slightly brown as opposed to black colour in volume. Also the oil cap has a bit of brown gunk on it.
This is the first time I have used Castrol RS 10W60 so I dont know if that is the cause. Is the head going porous or is the head gasket bust? How do I tell? The car has never over heated and has been regularly serviced with no abuse. I recently changed the coolant and everything there was normal. I have checked the oil a few days after the change and the colour seems ok on the dipstick.