Help! Did I screw up my Coolant Flush?

[ExpyAlaDocious]

2005 4x4 Expedition w/ rear heat.
163kmi on Odometer, engine replaced at about 95k mi w/ a used replacement engine w/ 63k mi on it.

I inherited this truck, so don't have much knowledge on it. I'm handy, but a moron noob when it comes to cars- go easy on me...

I live in AZ, and it's super hot here (118+ degrees outside). Sitting idle in the drive thru lane for a while, the truck overheated on me. It popped the degas cap, sprayed coolant all over the engine bay. Let it cool, filled it with drinking water and limped it home. Drove it for a few days, no problems whatsoever since. I decide to flush the coolant, since I doubt it's ever been done before. Found the Ford Tech's youtube and followed the steps as follows...

Basically, drained it via the radiator petcock, then added the coolant flush cleaner and garden hose water to the fill line. Ran the truck to temp w/ heat on front/rear, drove it a few miles, and drained again. Then I ran the garden hose to the degas bottle, left it overflowing the bottle and the drain open, running it through the system until it ran clear (took about 45min w/ engine running, revving it to 2500 rpms once in a while, etc). Felt confident it was 'clean' at this point, so closed it all back up and added 50/50 mix of Gold coolant and distilled water...

BUT- it only took about 2.5gal of the 50/50 coolant, and the manual suggests 20.7qt (just a little more than 5gal). So that means there's about 2.5gal of garden hose water still left in there...

QUESTIONS:

1) Should I drain it all again and add new 50/50 mix, and if so, how do I get the remaining 2.5gal of water that's still in the system? Or should I just drain about a gallon out, and had a new gallon of full concentrate back in? The manual suggests a 40% mix in my extreme heat climate.

2) I DID NOT change out the thermostat, but I see how cheap/easy it is to do... I assume I should do this as well?

3) Any other maintenance type items I should do while I'm performing any of these other things?

Thank you all for your insights!

 

[whtbronco]

I would drain it again to get the tap water out. Make sure you get a new thermostat gasket as well. Locally I can get the Ford o-ring gasket for the same price as the Felpro at the parts store. RockAuto is much cheaper though, but shipping is killer.

When I flush the coolant in mine I drain the radiator and pour distilled water through it until clear. Pull the thermostat and the heater hose at the intake manifold. Pour distilled water into the manifold port until it runs clear. Disconnect the return heater hose and then pour distilled water through the heater hose removed from the manifold and do this until clear. Now you have pretty much all the old coolant out, but it's mostly filled with distilled water. So start pouring concentrated coolant in until you see the coolant start coming out both at the heater hose and the radiator from pouring coolant into the manifold port. Now you have at least 50% coolant. Fill the radiator with concentrated coolant in my case until I have 4 gallons of coolant and fill the rest with distilled water. Mine holds 6gal.

I know the recommended is 50/50, but I have never had poor cooling using a higher coolant percentage.

I also never put tap water in my coolant system anymore, but a lot of that is due to the amazingly terrible water in my area. That said coolant will not lead to corrosion, distilled water might though unlikely, tap water will. Coolant can turn acidic with age and will eat everything from the inside out if not changed.