Coolant top off procedure

[AudiEmpire]

Probably over thinking this, but better safe than sorry. Noticed my coolant level is almost an inch below the MIN line; however, I don't have any warning lights. I have a 1.5L bottle of G12 coolant (pentrofrost SF) and a gallon jug of distilled water and plan to add a 50/50 mix until my level is at the midpoint of MIN-MAX.

Is there any special procedure needed to prevent air from entering the system? I'm assuming I should add coolant to a cold engine and let it sit for awhile?

Any thoughts are greatly appreciated. Thanks!

[sitting proper]

You're totally over thinking it. Just put the G12 in until the MIN spot on a cold engine, you can dilute it if you want to, but if you're only adding a little bit it wont do any problems to the system straight G12.

[MunkySna]

so what about g12 vs g13 for ours cars?

[mdhagan]

Either works. Really any coolant meant for aluminum motors works, but that said, I'll always pay extra for the VAG stuff

[AudiEmpire]

Quick Update : I added approximately 1L of 50/50 G12 coolant and distilled water mixture to the expansion tank, which brought the level back up between MIN and MAX. No issues in 3 days and 60mi of driving, I haven't located any leaks in the tank or hoses, so still unsure what caused the low coolant level.