Pretty straight forward. But is was awhile ago I did it.
If you want to do a complete flush:
Drain radiator at radiator.Refill with plain deionized water(this has been debated). Run truck for a few minutes adding water as needed.
Repeat until water drained is clear. Refill with straight (orange) extended life coolant after final drain.IIR the capacity is 20 quarts,someone will correct me, so you will need 2.5 gallons to 3 gallons coolant back in. I don't have my Helms handy.
Run with coolant tank cover off at 2000 ir so RPM untill it burps air and top off with 50/50 coolant if you have no straight coolant left. This is in general.
Check level and coolant range of protection.
If you only want to drain off half ,drain radiator replenish with 50/50 extended life(orange).
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!