This Preliminary Information communication provides information to the technician about servicing any of the cooling systems on the these vehicles, which includes the High Voltage Battery Assembly, pumps, reservoirs, hoses, air separators, radiators, PIM, engine or heater system it is important to use the proper coolant and water mixture. The Power Electronics / Charging and Battery Cooling systems require a 50/50 mix of GM DEX-COOL® and de-ionized water.