Did an oil change and a coolant flush this last Saturday. Definitely needed both.
The oil went about 3,600 miles. It was black, and low. I have an oil leak
The coolant flush was weird, but I think it helped. Didn't use any flush chemicals. I was scared of creating problems. ie- a leaky heater core. Mine is original.
I used one of those flush tees hooked up to the hose between the heater valve and cylinder head. After I drained all the coolant I filled it up and started flushing with the engine running. First draining out of the petcock hole, and then I had this "splash guard" that came in the same kit as the tee. Filed that down to fit snug in the radiator neck, and then had to increase the amount of water going in so that it would push water through the top of the radiator. 5/8" heater hose fit inside the splash guard so I could route it out of the engine bay.
The water that came out was a murky light brown. It eventually ran clear from the petcock and then moved on to the radiator neck.
Once all of that was good I drained all of the remaining water. Even opened the block drain. Nothing was in there after having drained from the petcock.
Tip: A really long extension and a 14mm swivel socket can reach the block drain from the front left fender well. Above the frame and beneath the sheet metal there is a gap.
Filled with 50/50 mixture of Distilled Water and Ethylene Glycol Coolant of choice. (O'Reilly Green in my case)
I'm skeptical about leaving the tee on the truck. I may pull it and replace with a straight section of hose, will keep for future use. Also I don't think the placement was optimal for flushing. If I do this again I will put it on the passenger side of engine after the water passes through the heater core. Because of where I placed it, water had to go through the heater core, and then to the water pump. Heater never got hot hot while flushing as you can imagine.
Sorry for the long post, but hopefully this helps someone in the future
