Hi guys, probably going to sound like a dumbass here, but I need to change the radiator fluid and was wondering how to do it. Doing a service and this is next on the list.

Shes a 92 Nissan Safari with a TD42.

Any recomendations on what coolant and what ratios to run? The average temperature in my area ranges from 7 degrees in winter to 25 degrees in summer.