I would also recommend the G-05.
Around here, CarQuest sells the Zerex G-05.
It is usually up to the individual store as to what products they carry, so 1 may have it.....and another not have it.
I think that initial change interval is 5 years......but read your owner's manual, or look it up online.
G-05 is a bit more expensive than some other coolants out there, but it is worth it.....good stuff.
Pay attention to the indication on the jug......if it is concentrate (which you would mix 50/50 with distilled water) or premix (which you would NOT add anything to).
I have had auto part store clerks try to sell me something else....telling me that is IS G-05......if it does NOT say that it IS G-05 on the label.....it is NOT.
If you have an issue locating it.....sometimes the Motorcraft brand at your local FORD dealership will be around the same price...maybe even cheaper...depending upon what the dealership is charging.
If wondering if you have a leak into the oil, you can send in a sample of your used oil to have it tested, and they will let you know.
I have used blackstone labs....visit their website for instructions and a free sample / mailing kit.