I'm not sure if the dealerships will accept an international wire transfer, as it's not exactly the same as a normal CBU transfer. This hasn't worked for me in the past with other purchases.
If you are a resident/ are able to open an argentine bank account, the best option is to wire yourself money via Western Union and then pay at the dealership via bank transfer.
I'm currently buying a used car and private parties want cash. I'm buying with my Argentine boyfriend who has a banco Macro account, so I ended up sending him various Western Union bank transfers (as advised in previous thread here). However, when we tried to withdraw at the cash at the bank, they said we needed to prove that we were a couple (had to get police verification that we live together) and I had to provide proof of income and documentation of my bank account and transfers to be able to withdraw. Apparently if I had gone to an escribano and declared the money as a donation to my boyfriend, that would have sufficed. Ultimately I was able to do so, but they gave us the very large sum in 100 peso bills that filled an entire backpack.
Anyway good luck, let us know what you find out!