I have been running Evans NPG ( the original formulation) since late 1998 in a 1995 Ram Magnum 5.9V8
My original interest was whether it would reduce pinging on 87 octane gasoline in 95 degree F weather.
It did not.
I have continued to run it though, and am just short of 205,000 miles.
When the outside temperature falls below 25 degrees F the Evans NPG "overcools" in the radiator and you have to downshift to keep rpms up so that the pump will force the sluggish and viscous coolant through the system.
The NPG does seem to keep internal corrosion at a low level.
About five years ago the driver's side plastic tank on the radiator began leaking and i replaced the whole radiator. Whether the NPG coolant chemistry had anything to do with this is unknown.
I have run 205, 195, and 180 thermostats.
The 205 thermostat gave slightly higher fuel economy.
If a 230 degree thermostat was available i would try it.
I have run without the cooling fan bolted on for as much as a year in both winter and summer weather.
A few years ago i got stuck in an Atlanta traffic jam in 95 degree weather and got uncomfortable as with the air conditioning running near full blast the coolant temperature went up to the 280 degree range... but nothing bad happened.
A couple years ago i bought a zero psi radiator cap and have been running it.
http://www.summitracing.com/search/depar.../cap-logo/stantI went to the Stant 0 psi cap because i have a weeping coolant leak at the top drivers side timing chain cover gasket, which is the 1995 factory original.
