[Razorback1980]

I'm not an antifreeze expert, but I do know that 50/50 is recommended for higher boiling point/freeze protection and corrosion prevention. But over 70/30 and boiling point/freeze protection and corrosion prevention actually decreases. As for water cooling better than the mix, I couldn't find information on that but it would be interesting to know for sure. Phosphate free, that's a requirement mostly for Europe more so than the US. Apparently the phosphate which is added for corrosion protection will cause deposits in European water and not so much so in the US....according to Prestone anyway. Since Porsche designs cars in Europe, it makes sense they would recommend phosphate free coolant. The part I would like to learn about but couldn't find anything about was which antifreeze was unsafe for aluminum engines and why. What ingredient is added that makes it unsafe for aluminum engines? Anyone know this?