In 1977 I cosigned on a loan for a lovely Kawasaki motorcycle, since my then-boyfriend's credit history was insufficient. He made two payments and disappeared into thin air, and I had the privilege of continuing for two years to pay for a bike that I could neither ride nor sell, since the ratfink took the Kawasaki with him when he left town. I could have defaulted on the payments, of course, but that would have damaged my credit history considerably, and would also have been a dishonorable thing to do.
My advice: Never, ever cosign on a loan unless you are willing to consider the full amount a "gift" later on.