21-01-2019, 01:56 PM
The fuel returning to the tank is not filtered, it comes straight from the injectors/hp pump. My personal theory is that the swarf (it's not rust) is actually from fuel station pumps wearing. There is a popular theory that suggests it is from lift pumps wearing, but I have seen the same swarf in hundreds of vehicles, most of which don't have lift pumps. Whatever it is it's not an indication of any problem with your car and doesn't appear to cause any issues, so not worth worrying about.