At $168 for 5L of the genuine coolant (pn STC50530 - I hope that is at least concentrate) I'm looking at alternatives and noticed that Havoline Extended Life Coolant (XLC) (Caltex ELC) is silicate free when compared to the Penrite equivalent product which not silicate free (si-OAT). Does it matter if the coolant isn't silicate free and has anyone got experience running with Penrite?