I'm not sure that AA vs. AB identifies the coolant type. It may be the digits. Someone versed in FCA part numbering schemes should be able to help decipher.From this thread (http://www.giuliaforums.com/forum/778-alfa-romeo-giulia-issues-problems/32033-low-coolant-level-2.html):
Here's the fun note from the TSB for a few years ago: "NOTE: If OAT (MOPAR P/N 68163848AA Purple) has been Mixed with HOAT (MOPAR
P/N 68048953AB Pink Or Factory Fill HOAT Orange (Fig. 2) or (Fig. 3)) or any
other coolants have been mixed, it will be necessary to flush the cooling system."
OK, so having read that, you search the 68163848AA part number and keep getting jugs of coolant that meet MS.12106...so I have no freaking idea what the heck we should do now. The one clear fact is that the "AA" letters identify OAT coolant and the "AB" letters identify HOAT coolant, and never the twain should meet.
So what are the odds that we will be able to rely on dealer service departments to use the right coolant?