I need to replace my coolant. I want to drain & fill up w/ distilled water run engine for 10 minutes to mix water & coolant & repeat the drain/fill/drain process again. This should get rid of most of the old coolant. I will fill up w/ pure 3.5 gallons of 100% HOAT coolant & top off w/ distilled water- this will give me an approximate 50/50 concentration.

What radiator/heater hoses do I remove to drain the most coolant? I was going to fill w/ Zerex Gold - any other coolant recommendations?

 

The standard method is to open the radiator drain which is near the bottom on the driver side and drain there with the radiator cap on(surprising I know). When I did this and refilled it I took the thermostat housing and t-stat out for the refill and was able to avoid any issues with air in the system causing temporary spikes in temperature..

 

Mark, I simply drain the radiator into a 5 gallon bucket from the draincock. Replace the draincock and refill with a 50/50 mixture of Zerez G-05 and Distilled water. Personally, I think it's a good idea to have a 2nd draincock available in case the plastic threads get buggered up. But my original is still working fine.

From my experience, it will drain out about 4.5 gallons or so. So I put in a gallon of Z.......then a gallon of DW........then a gallon of Z and another gallon of DW....then finish it off a little bit and a little bit till full.

I haven't flushed. I just simply drain and refill. Then I do it again 20K miles later. It keeps almost new stuff in there all the time and it's easy to do. I don't worry about getting as much as possible or all of it out.

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Mechanic at work drains the old, then fills with a solution of water and Calgon.(you know the commercials...Calgon take me away) Then adds a little water to fill it up and runs it for a while til it gets to operating temp for a while then flushes with a hose until it runs clear. then fills 50/50.
He swears by it.

 

Personally, I drain it and unhook a heater hose. Then hold a running garden hose up to one end until the water running out other end and overflowing the radiator turns clear. Then run water through the other way.

Water here is very low in minerals, so once the tap water has all drained out I just dump in a couple gallons of distilled water through the engine into the radiator and out the drain to flush out any remaining tap water.

Then put the hose back, close the drain and fill with 1/2 or a bit more of the published capacity with anti-freeze and top the rest off with distilled water.

There might still be a little trace of tap water in there, but I've never had a problem.

I'm not a fan of using commercially available chemical flushers, unless the cooling system is really in bad shape. Since I always change the coolant on schedule, on my own vehicles things stay clean.