NGP+ coolant.

[davidf]

Anyone ever use this in the GN?

 

[Robert Wilson]

I have used NPG and NPG+ for more than 10 years. I can't say that that I have gained anything by using it but the theory sounds good.
Special attention is needed to purge the air from the system to make sure it doesn't air lock at the water pump. I added a brake bleeder at the water pump for this.