I just saw my coolant has gone from green to a muddy color. I put off doing this flush for too long it seems. It my first time through the process on this 03.

My delta is always within 4-7 degrees.

Should I use VC9 while flushing? I've read some say yes and some say no. The more I read on it the more confused I am getting. I bought the truck several years ago and have not flushed the system yet. The Ford dealer said it was flushed when traded in but who knows if that was true or not. All I know is the coolant isn't green, it more of a muddish brown. I will be replacing the thermostat, housing, upper and lower rad hose, and degas bottle along with the flush this weekend.

 

I would lean towards not using VC-9, since your deltas are good. But muddy color isn't good, also there should never be green coolant in a 6.0. The original was Ford Gold which is yellowish. Most people on this site have switched to a CAT EC-1 rated coolant.

There should be a nice write up in the tech folder on how to flush your cooling system.

 

Why not? VC-9 is doing the job.

 

VC-9 is an awesome iron cleaner, but the OP uses it in his current state he will be investing in a new oil cooler in the near future. The VC-9 will generate a lot of crud the will clog the oil cooler.

Since the deltas are good, just flushing and changing the coolant is much gentler.

 

I recommend backflushing the oil cooler during any cleaning work on the cooling system.
Unfortunately, you can't get oily residue out of the system without chemicals. Some use detergents I also use these products:

 

One issue you will have using VC-9 or Restore Plus (both are the same) is that some of the rust scale being shed from the block will not dissolve fully when flushing is usually done. I ran both of those one after the other for a total of 5 hours driving and still had scale in the intake port of the cooler. Back-flushing the cooler with the water pump out may have helped, but that was talked about at the time, and I didn't try that.

There is another product out there that I haven't used, but a few have. It's a coolant flushing product from Evapo-Rust called Thermocure. I use Evapo-Rust (another product) all the time to remove rust from objects; it's a better product, although not as quick, as white vinegar or acids. And in fact, I used Evapo-Rust to clean my heads and block coolant passages when I had the engine apart. It worked exceptionally well.

The people who have tried Thermocure (not an acid) said it worked extremely well, too, but I haven't directly tried it.

By the way, I know people have warned that too long of time using these products might damage hoses, plastics, or aluminum. I ran three runs of acid-based cleaners during one week, a total exceeding 8 hours. One hundred thousand miles later, I still had the same hoses, Degas bottle, hose wye out of the Degas bottle, and none of my aluminum showed degradation when I pulled the engine apart. I also still had some residual gel in the oil cooler from using G05 gold coolant after using Restore twice, so it's not perfect, but it did clear out 60% of the gel. Some have said Cascade with Dawn works better as a gel cleanser, but I never tried it.

 

The only flush I would do is a distilled water flush until your green coolant is gone.

 

it's not really green anymore but that is the way I am leaning. I did order some VC9 online, but was sent VC1 instead.

 

the coolant I ordered is CAT-EC 1 rated so I am good there. It's all coming out one way or another on Friday. I am also installing the Fumoto F108N valves after I clean most of the crap out along with the new hoses and t-stat/housing.

 

What I have so far...
Upper and lower rad hoses
New degas bottle and cap
New t-stat and housing
New fuel filters
New oil Filter
15 qts of Vavoline 15-40 (still have 2.5qts from last oil change)
6.4 trans pan and filter
30 qts Motorcraft LV
​​​​​​EGR reseal kit
Blue spring kit (repair shop broke and replaced fuel bowl.. I'm not sure if they put my old kit in it)
2 qts of VC1 (shipped wrong item and returning)
Fumoto F108Nx2
​​​​Archoil AR9100

Yep going to be a busy weekend LOL....