there are no drain plugs on the engine. Only freeze plugs. you could have some serious trouble here as green and Orange coolant do not mix. But the best thing to do is get as much coolant out as you can and get some radiatior cleaner like prestone, that has oxyalic acid in it and follow the directions on the bottle. YOU DO NOT WANT RADITOR FLUSH. then pull the lower rad hose to get all the crap out. before filling iwth coolant however have the system checked for a bad head gaskets /intake gaskets, quite common on these, that's is why the guy kept adding to it.Normally head gaskets on these will leak to the outside of the engine.

Answered by hmac300 (expert)
17,879 answers provided

Thank you for taking the time to reply but I already understand that the "best thing to do is get as much coolant out as" I can. What I asked was "how do I completely drain,flush and clean every single hose, tube and passage way the coolant sees during its circuit?" If you could detail that process step by step I'd really appreciate it.

Response from jamextras
3 questions asked

the only thing i can advise here is stick a hose into the radiator ro buy one fo the kits that hook up to the heater hose. open the petcock on the radiator and start ther truck up. copletely draining the system like you want to do is very hard and without running water through it is about the only way to do it.

Answered by hmac300 (expert)
17,879 answers provided