LariatDude

This for the 5.4 3v. 124,900 miles and an 05, the coolant doesn't look like it's been changed. The degas bottle also has residue on it. I've researched it but I want to be certain. This is how I would flush it (if I even need to?):

-Drain radiator from the petcock
-Fill with distilled water until the level is between the fill marks
-Remove thermostat and start engine (to circulate water through block instead of waiting for operating temp to come up)
-Select full warm (90 degrees) to circulate through heater core and let idle for ~10 minutes then drain distilled water
-Repeat steps above until water drains clear
-Replace thermostat with new one
-Measure amount of distilled water drained, then compensate for what remains in the block with concentrated Motorcraft VC-7-B
-Start truck with temp still set to 90 degrees, allow to reach operating temp and add until level is stable, then drive around and keep checking level.

Then I'd check the protection with the coolant checker meter I bought from Harbor Freight. Is this okay? Do I run the risk of plugging the heater core? Or should I just do a simple drain and fill of Zerex G-05? Thank you.

HubFord

Sounds good, but the question below intrigues me.

How much remains in the block when it's "drained" from the radiator?

If it's very little why not flush with tap water?

Also, what about using a flushing agent?

LariatDude

Well the manual states less than 80% coolant is removed from the system. I've read elsewhere that they were only able to drain around 2.5 gallons since much of it remains in the block. As with the tap water, I just don't want to risk any build up or corrosion. I'm not sure how hard our city water is but I figured since distilled is 88 cents at walmart, why not just use that? As for the flushing agent, I've also read there's a risk of it putting holes in your radiator and causing leaks? Just didn't want to risk it. But if it's safe with this mileage and original radiator then I'll use it!

HubFord

What is the total gallon capacity of the cooling system?

nrivera04

Swap steps 2 and 3. Take your tstat out first.

That’s a bit much if you ask me though. Just pick up a bottle of zerex/prestone flush and follow the directions. Refill afterwards.

HubFord, the total capacity if I remember right is about 4 gals.

nrivera04

I take that back, closer to 5 gals total.

LariatDude

Yeah I was thinking last night I might as well just flush it with the chemical then drain and fill with motorcraft 50/50. Although I'm not sure if it's in the directions but how would I make sure I don't leave the chemical flush remnants in there?

techrep

iTrader: (1)

Need to use the flush first.. and then flush again with just distilled till system is clean. Motorcraft gold does not come mixed 50/50.. you will need to mix it with distilled which is what you will already have left over in the system, that can’t be drained.

BryanKephart

Fordtechmakuloco has a video on YouTube. He used a hose. When I did my truck I had three gallons of FULL Strength Zerex G05 I think it was and then 3 gallons of distilled. I didn’t use I want to say I used 5 gallons total to fill the system.

By the way if you are going to be removing the thermostat, why not replace it. Buy the gasket too. I used Motorcraft, it wasnt that expensive

LariatDude

I'm curious how much distilled water stays in the system. I'm not sure if having more water than antifreeze ratio would cause harm. That way I'd just pour concentrated MC coolant into the system to mix with the water in the system, good idea. And yessir, I meant I'll replace the therm as well