winkawak

Been doing some research on the subject before i proceed.
Havent got under the car to check, is the petcock located on the passenger side (yellow ****)? Does our radiator have a bleed valve?

Please let me know if im missing any steps
1. with cold engine, remove reservoir cap and drain radiator petcock
2. tighten petcock and fill system up with distilled water
3. start engine and have heater on max idle for 10-15mins
4. watch temp gauge and add more water if necessary
5. turn off engine let it cool, drain the water
6. refill coolant, turn on engine
7. have heater on max, top of coolant
8. let it idle 15min with reservoir cap off to burp/bleed air out o f system

CaptStang

My 2006 GT has a little more than 100K miles. I flushed coolant and replaced the thermostat.

Suggestion: Before starting check your coolant temperature level at the dash a few times so you know what 'normal' is before you start.

I followed a similar process but flushed with distilled water 3 times.

Fun factoid but only 2 gallons came out each time and the Mustang uses 3 gallons of coolant.

I tried cleaning the overflow tank. Wound up removing it and cleaning it out. Still stained but glad I got some of the crud out.

Refilled with 50/50 and after 50+ miles the coolant still looks good.

Thermostat nuts are all down facing so you need to remove most or all of the hoses to open up the assembly. Suggest moving the power steering fluid tank.

You'll need a thermostat and washer (sold separately). Suggest investing in hose clamp pliers too.

To get the hoses off move the clamps back 4 inches (not off but back on to the hose) then try using a pipe clamp or large pliers to rotate hose and break the hose seal at the Thermostat assembly.

I do not suggest using a screw driver to pry off unless you plan to replace the hoses.

Then follow 6, 7, and 8 above. Check coolant level the next day and a few days later after running / driving the car.

If you had checked the coolant temperature level before you may notice that the temperature gauge shows it's just a little cooler than before.

Dino Dino Bambino

Some of the coolant will remain inside the block so you'll never get all 3 gallons (11.4 liters) out.