I bought 7 gallons of peak charge nitrite free elc coolant that was 50/50 diluted cat-etc 1 rated for heavy duty pickups today. Then I went to Kwik Kar to have them pump out the system and change. Very quickly we discover that vacuum draining the system is probably not possible as we only got 8 quarts out lol. So he proceeded to ask if there was a drain on the system. I told him yes in three places; the radiator, the driver side engine block and the passenger side block. So then I proceed to suggest that he follow Hanes maintenance manual for flushing the system and draining. Step was to open all the drains, the radiator easy by hand, than driver side engine block was easy for him to reach so he started to try and do it. So I waited for him to proceed. He did not have the right tool and said nothing about this when all and behold I had the right 5/6 1/4 socket drive hex bit. So trying to get out of ther I proceeded to drain one side while he was gone. When he came back he did not want to drain the passenger side because of the starter solenoid in the way. It was three bolts guys. Cmon, my truck has a literal basement beneath it and drain directly beneath it. Sounds like I should be able to knock this out in less than 15 minutes if someone was handing you the tools. But they all stood inside as it must have been to hot for them…so I removed it. Took me 45 minutes I thought not bad. Then it came to draining it, he didn’t want to do it. Removing the thermostat was too hard for him to with three employees doing nothing for at least 15 mins Average per hour. So instead of proceeding to be there way past when I should have been. I put the plugs back on. Then we began to fill the system from there press vac system thing that we ending up having to tilt over into a flower bed can so that we could get the last 8 quarts out. Gosh that was our magic number. We got I would say 5.7 close to 6, I had 1 full gallon and I mean it over filled a bit. And there was a little bit losses at the beginning when he tried to put more in after draining only 8 quarts. So that was backed back in but it was a lot because I proceed to stop him from mixing my good coolant with another type of coolant and wasting the $140 I spent on coolant today. I would be confident to say we got at least 5.5 gallons in. After running the truck today and working it a bit on the pedal but not WOTing it but giving it some boost to get to operating temps highway driving for about an hour soils. It’s 20 mins on the highway both ways. Some stop light 55 mph for about 10 miles then 45 for almost all the rest. Seems to be that the coolant has been worked through the system as only an hour after letting the system cool down has coolant proceeding to drop a good 3-4 inches below the system. So what I believe I will do is wait for it to stop moving. Don’t drive it and then let pressure be removed through the degas bottle over time. How long should I wait to open up the system. Is it going to rise to the high heat and temperature and vacuum back and in then release into the degas bottle overnight? Filling it with more coolant? I hope someone could shed some light. Am I wrong or right about this process.