Quote Originally Posted by mudski View Post
50/50 mix I do on mine.
That's what I run mine at. However when I was having temp gauge problems in Tassie late last year & changed the sender unit, we lost a reasonable amount of coolant & the guy at the radiator place in Burnie topped it back up with water. I asked about this as I wasn't keen to have the coolant over diluted. He tested the coolant with a litmus (or similar) strip & showed me that the coolant was 'strong' enough to do the job. He told me that higher ratios than about 30% didn't give any extra benefit.

That said I'll probably stick with 50% just so if I do end up having to drop some coolant, or get a leak out in Woop Woop I can top it back up with water & have a reasonable chance of still having sufficient coolant strength.