RUT is 9 digit number which every resident has and uses it very similarly to an ID number. It is connected to all purchases, accounts and legal actions. However the type of RUT needed in order to buy a car or a property by a foreigner who's not a resident is obtained from the tax office (SII) and not from the civil registry (registro civil). That's why a non resident can only buy a car at the notary and not directly at the civil registry like residents do. This type of rut is called an "investment RUT" and it always starts with the number 48.
TIP: after buying a car at the notary you will be registered at the civil registry (as a car owner, not resident) so it is possible to sell your car at the civil registry which is faster and cheaper.
How do I get a RUT?
In order to get a RUT you will need a sponsor and an address in Chile.
You can ask a Chilean friend or your hostel manager to be your sponsor, however they might be intimidated by the legal responsibility or just not know the process well enough so you will lose precious time and get frustrated from running around from one office to another, not to mention the SII officials make lots of mistakes that can cause future problems such as discovering at the end of your trip that the car didn't pass on your name because of a rut mistake. The service of SuzSantiago is a useful resource and the easiest and safest way to get a proper RUT number for buying a car.
Get the RUT application formulario
You will need to go to a Servicio Impuesto Interno (SII) which is a tax office and ask for an F4415.1. formulario. fill out this form with your personal and sponsor details as required.
NOTE: this is not necessary if you use SuziSantiago's service.
Find a notary.
In Chile every process involves a notary. make sure you find a decent one.
Go with your sponsor to the notary, have the sponsor sign the form with his fingerprint and notarize the document.
Return to the SII
Go back to the SII office and hand them the RUT form. make sure you receive a receipt (comprobante) internet code and username.
After receiving these documents log in to the SII website, reset your password and obtain the E-RUT. Print this for border control.
NOTE: Suzisantiago's clients only go to the notary to sign, the rest of the process is done by us without the client. later in the day our client receives the PDF and printed E-RUT.