[Blas]

Preston’s flush works well. Empty then Refill with regular water, run engine as directed, then I flush twice with regular water, empty system as best you can the refill with a mix of distilled water and Antifreeze going heavy on the Antifreeze portion because there is water trapped in the system in the block. I never buy the premix Antifreeze. Remember to open the heater control valve when you start the process. I recommend a bottle of water wetter in the final mix. Proper fill height in expansion tank is up to the divider inside the tank. Over filling is not a problem as the system will expel any extra Antifreeze thru catch tank. Remember to empty the catch tank when you start the process because if on the system refill, the tank gets filled to top, it cones out the ent hole on the top and the fans do a wonderful job of distributing it all over the engine compartment.
Biggest pain is getting all the air out of the system on refilling. I always use a vacuum refill system. If you don’t own one, I thing you can borrow one from most auto parts stores, or you can carefully loosen the water temp sensor on the top of the intake manifold and bleed the system. Nor Radiator cap on for this method and engine must get hot to circulate coolant thru engine. Most SPF’s have a drain on the lower radiator hose connection. You will want to replace the copper crush gasket on the drain plug. Remember, Antifreeze is poison to animals and people and bad for environment, oil change shop recycle the stuff for free here.
Blas