Recently acquired 2018 F150 5.0. I started out researching what coolant to buy to top mine up. I've decided to change it out to the newest version, the yellow stuff. The truck only has 30000 miles on it so I'm not planning to use any chemical flush.
Here's how I thought I would proceed:
Drain the rad, run the truck briefly, drain the rad again.
Fill with distilled water
Run the truck up to temp, heat on.
Drain the rad. Repeat the process till it drains nice and clean. (distilled water is cheap).
Now the system is supposed to hold 13.9 qts total so I'll pour 7 qts of concentrated yellow into the rad and then top up the system with distilled water.
This should give 50/50 mix.
Only thing I'm wondering is if the rad and whatever I can get drained out will leave enough room for 7 qts of concentrate. I'm assuming what's left in the block is less than 1/2 the entire capacity?
What do you all think?

 

I would think you should be okay as the orange & yellow coolants are compatible, so if you don`t get the orange completely out it`s no large deal.

 

You should use the 50/50 pre-diluted coolant to ensure you have the correct concentration. Don't worry about the coolant mixing the yellow is backward compatible with the orange. But keep in mind that when the yellow mixes with the orange the orange will be the dominant color.

 

On the right track. My 2011 3.5 takes five-six drain/refills with distilled water to flush out the old coolant. Pretty close to half of the 16 quart system remains in the engine. Takes two gallons of concentrate to refill. I don’t know how much your 5.0 will retain, but do the math and use concentrate.

 

If I drain and fill it several times with distilled water by the end there should be just some water left in the block after the final draining. If I add 50/50 the remaining water will dilute it too much.

 

Distilled water is pretty cheap but I need to find a local source for gallon jugs of it.

 

I did the same thing, using 16 gallons of distilled water. One additional thing I did, on the initial drain, I removed the thermostat, so I had full flow. After flushing I installed a new Motorcraft thermostat, purchased from the dealer, so I was sure I got the correct thermostat.

 

For me, because of disposal issues, I leave this task to the dealer or 3rd party, JMO. Distilled water is close to 3 bucks a gallon here now, that would be $48 bucks alone plus the disposal.

 

Just an FYI, our local Jiffylube oil change place takes antifreeze for n/c. Learned that when I drop my oil off.

 

I used 15 gallons of distilled water to be completely clear. Then I drained one more time and added about one gallon of concentrated coolant ( I bought 2 gallons), ran up to temp again and drained out another gallon, including some of the new coolant, now heavily diluted, then added the rest of the of the 2nd gallon. Should be about 50/50 mix.

Here' a calculation someone had previously posted