The Wallabies have been beaten twice by New Zealand and once by South Africa, but they eased past the Pumas thanks to six tries in Canberra.
However, it was the South Americans who scored first through Martin Landajo and, with Nicolas Sanchez landing the conversion and a couple of penalties, the visitors led 13-10 at the break.
Folau scored his first try in the 29th minute and went over again on 53 minutes as the floodgates opened, with Sekope Kepu, Nick Phipps, Will Genia and Jordan Uelese also scoring tries while Bernard Foley kicked 15 points for the hosts.
Matias Moroni touched down for Argentina late on but it was no more than a consolation. Daniel Hourcade's side remain pointless after four rounds of matches.