Coolant Flush Procedure?

Hi all,

I am going to be changing my coolant soon along with a bunch of other maintenance. I've got a bottle of the Ford VC-1 "Coolant Flush," but the directions are as follows:
1. Add flush to cooling system with the old antifreeze/coolant in it.
2. Run flush process for 10 minutes.
3. Drain the cooling system.
4. Flush the cooling system with clean water.
5. Install new antifreeze/coolant.

What is meant by "run flush process?" And just to be really cranky about it, why is "run flush process" different than "flush the cooling system?"

Cheers!

I think it means to run the engine after you put the flush chemical in it.

There is no ForScan activation of that coolant valve/regulator required at all, correct??

I think this means that the coolant is circulated by a Coolant Flushing Machine. So basically you add the coolant Flush solvent solution to your your radiator via the machine, then rinse everything well with water, evacuate the water and then Vacuum fill the cooling system. Basically what you have requires equipment you don't own. I also suspect that if you try running your engine with this solvent package in the coolant it may result in damage to your engine or colling system. Because it's probably mix of chemical that will clean and oxidation or buildup in the radiator and engine.

If you really think your cooling system needs flushing then I would advise you take your bottle of Cooling System Flush to a dealer and have them do the works. I will also note that the primary reason I only use Ford's coolant is because I know from about 50 years of experience that mixing coolants can cause "interference" issues between different brands formulas. If you've been mixing coolants a flush is a good idea. If you haven't you have been running a coolant specifically designed for aluminum block engines and aluminum radiators and a flush is only needed about every 10 years.

You don't need a machine to use the VC-1. Here's an instructional video.
View: https://youtu.be/RWIXa50R9bo?si=wTmyPNhknWm2BzC_

I find that as long as you’re willing to spend the time doing vacuum fill between steps, its better to first drain old coolant, fill with distilled water + flush, run the engine until
till the heater blows hot, then do a rinse (or two) the same way (fill, start car, run, cool) before filling with new coolant, especially if you’re not sure what type
of coolant was in it before

Just takes a lot longer because you have to bleed the system every time to make sure the flush gets into the heating circuit, and let it cool down afterwards.

Whenever you drain coolant, not all of it actually comes out - a decent volume remains trapped in the engine block as well as the heater core. With a couple cycles of water and water/flush with the engine running (only way to actually move stuff around in the system). You are essentially diluting out all the old gunk and coolant.

That said, you can do it the way in the instructions, as long as your system is not that old and you are refilling using the exact same coolant type that was in before (orange or yellow)

I've never seen anything that suggests that there is.

Thanks for the help, everyone. I figured it was something like what everyone is describing, but wanted to make sure. I'll be doing at the work with a garage that may have a vacuum fill machine and I am replacing the old orange stuff with the new yellow stuff - Ford's service bulletins expressly say that the orange and yellow can be mixed.

The video goes over draining and flushing with a draincock, but our FiST radiators don’t have one. Would we just leave the lower radiator hose disconnected from the bottom of the radiator to flush water through the system from the bottle on down? Then just reconnect the hose to refill the system?

Yes. Drain the coolant enough that the VC-1 will go in, put the VC-1 in with the old coolant, run the engine, drain the full system, flush with clean water, then fill with coolant and remove air. It's the same procedure but you just don't have a petcock to drain with but instead use the lower hose.

Following the service manual you open the reservoir cap, take off the lower passenger side radiator hose and let it drain. Reattach the hose, vacuum the system and fill. Fairly quick and simple.

Following the service manual you only get out, about half of what's in there. This fact makes it risky to refill with anything other than the normal coolant that Ford recommends. If you fill with water for instance, you'll need at least two cycles of full-temp run and drain before there's reasonable assurity that you've restored proper freeze and corrosion protection. Running flush, risks leaving a significant amount left in there... and for reasons @scooter123 mentioned, this can be bad.

What I've resided to do with my own vehicle is, simply swap out the coolant more often. Maybe twice over six months, then leave it alone for some 80% of the recommended interval.

https://www.fiestastforum.com/threads/unable-to-pull-vacuum-on-cooling-system-resolved.28344/

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