i found two versions of opening the heater core valve when flushing the cooling system, not sure which is correct. basically, operate the climate control till a certain code appears.

first steps are the same for the 2 versions:
1. switch on ignition
2. press "off" button of climate control 5 sec

after that

service manual version:
3. press "hot" button till "32" is indicated
4. press "DEF" 2 times.

ORG sticky version:
3. press "Hot" 3 times
4. press "DEF" 2 times, code "43" is displayed.

both end by waiting 10 sec before turning ignition off.
i think the service manual is wrong. what do you do when flush the cooling system?

 

I used the org version, I actually drained first it was done, then I remembered I forgot to open the heater core, follow the stickes on it, opened it and more coolant came out ( a lot more ), wash out and refill.

dont know what the concequences of what I did was, but I didnt have heat for a while, unless I had it on the hottest setting.

 

I don't flush, just drain and replace whatever comes out every 2 yrs.
Been doing that with every car I've owned. Never had a cooling system fail on me.