http://www.evanscoolants.co.uk/
I am thinking of trying this out in my 405, just wondered if anyone has any experiences of it or knows if it as good as is made out?
The reason I'm considering it is that it won't freeze (until -40 Celsius), it won't rust anything like the radiator and it will supposedly never need changing. However it is quite pricey, I think it would work out at around £100 or so to get enough for my 405.