Brian,

I have Evans installed in my 603 engine but have little data since I haven't put many miles on the car.

In my 617 engine I am satisfied with the performance of the Evans for about 2 years. Yes the engine runs hotter up a long hill like in the Rocky Mountains than it would with conventional coolant but as soon as it gets over the top of the hill, it cools quickly. I have seen the temp gage up to 250*F for short periods of time with no boiling, coolant loss or pressure in the system. But I have seen it hotter with conventional coolant in extreme conditions. The red line on the temp gage is 260* and that is probably because that is the maximum temp of conventional coolant and not having it boil.

P E H