The easiest way that I have found to fully/completely flush the S/C cooling system is to use a simple Shop-Vac on the blower side.
This will work for the 2007-2012 and 2013.14 S/C systems, but for the Step Number 4 below, do not completely remove the S/C reservoir hose from the upper nipple but instead a 3/4" 18mm plug will need to be installed in the hose end that was removed from the I/C nipple and keep the original hose attached (upper and lower) to the reservoir, but use the rest of the procedure outlined to blow the old coolant out, completely flush with clean water and then refill the system. I guarantee the dealership will not fully flush the system in this way.......
1 - Completely remove the upper hose on the S/C reservoir. 2007-2012 only, 2013/14 outlined above.........
2 - Install a 3/4" - 18mm 90 degree turn-down hose on the I/C outlet nipple where the reservoir hose was removed.
3 - Place towels in the area below that installed 90 degree hose and place a large Ziploc under that 90 degree hose.
^^^That is the "catch end" for the old/contaminated coolant.........
4 - Install a 3/4" - 18mm hose cap over the S/C reservoir nipple where the upper hose was removed. 2007-2012. See above for 2013/14.
5 - Open and remove the S/C reservoir cap and using the Blow side of the Shop-Vac (with a towel wrapped around the Shop-Vac hose), blow the coolant out.
6 - Keep an eye on the Ziploc bag as it fills, to not make a mess remove the Shop-Vac hose from the reservoir cap hole as needed to empty the Ziploc. Of course the larger the Ziploc (Gallon size, etc.), the more fluid will be captured at a time.
5 - Put fresh water into the S/C reservoir, I used Distilled Water so there are no minerals or Chlorine in the water.
6 - Keep the S/C reservoir filled with water and keep blowing, air and water will come out at the capture bag, empty as needed. Continued to blow the clean water through until it is clear at the capture bag, this may take a few times of flushing with the clean water until it is crystal clear. then blow all water out of the system so it is empty.
..........Now the refill w/o air pockets.......
7 - Pour the new coolant into the S/C reservoir, it will gurgle and the fluid level will go down as the coolant finds its lowest level (gravity works). Keep filling the reservoir until it will fill no more.
8 - Now with the blower side of the Shop-Vac start the blowing process again, BUT THIS TIME be sure not to allow the coolant level to go below what you can see in the reservoir <<<<That is Very Important.
9 - Blow some coolant into the system, verify the level in the reservoir and ad as needed do NOT let that coolant level get out of sight in the reservoir. As you blow the new coolant through, it will push the air out into the capture bag along with some new coolant, you can either pour that captured new coolant into the reservoir or throw it away. I reinstalled that coolant in the reservoir, it is new coolant and my system was completely flushed with water until clean.
10 - Continue to blow the new coolant into the system (keeping an eye on the level in the reservoir) until there is only clean coolant flow out of the nipple at the capture bag and no air.
11 - Remove the capture bag and towels, the main purpose of the towels was to protect that Zip-Loc from being punctured by a fan blade, or a hose clamp tip or anything else in that area between the engine and radiator., plus the towel(s) also hole the Zip-Loc upright and in position under the discharge hose.
12 - Remove the 90 degree turn down hose from the I/C outlet nipple and also the rubber cap on the reservoir nipple. 2007-2012 cap and 2013/14 hose plug.
13 - Reinstalled the original hose connection(s) run the car to operating temp. ad add coolant as needed, most likely you will not need to add much, if any at all.......
No need for any specialty tools, a simple Shop-Vac, a Ziploc baggy, some towels and the rubber plug/cap mentioned above along with a "turn down hose".........
If you just want to blow it through and refill it, it won't take long, if you want to fully flush all of the old/contaminated coolant out with water for a clean system, it will take a little bit longer......
R