Ranjeet Matharu, 39, first kidnapped the "terrified" 18-year-old as she walked home alone along a deserted street and then ordered her into his rubbish-strewn van.
For the next two hours he forced his sobbing victim to submit to a series of sex acts.
As the girl begged to be allowed free, he then covered her from head to foot with after-shave, asking her repeatedly if she liked its smell.
Knightsbridge Crown Court heard that since the attack last June, the girl's life had been "destroyed" and she was now too scared to venture out alone.
Judge Francis Aglionby made it clear to Matharu, who has been disowned by his family, that he would either be jailed for life or sent to a maximum security mental hospital.
Either way, he said: "you will not recover your liberty for a very, very long time." He adjourned the case for a three-month psychiatric assessment, coupled with a restriction order on his liberty.
Matharu, of no fixed address, nodded slightly before he was led from the dock.
He was found guilty last November of two offences of rape, one of indecent assault, one of false imprisonment, and another of kidnapping. Psychiatric reports were ordered, but doctors were not able to determine the extent of his illness.
His victim had spent a pleasant night out with friends, but in the early hours of a warm summer's morning, set out for home. As she walked through Fulham, Matharu drew up.
He leapt out, brandishing a screwdriver, and ordered her to get into the van. He stopped the van 25 minutes later by the River Thames at Hammersmith.
He ordered her into the back of the vehicle, forced her to strip, raped her twice and forced her to participate in various sexual acts. Sobbing through most of her evidence, she said: "I was so terrified I couldn't move ... I thought I was going to die."
Finally, after forcing the youngster to tell him a name and address and phone number, he drove her to her front door. The girl staggered indoors, before collapsing and "screaming hysterically" for help from her sleeping parents.
The following night Matharu went on the prowl again, in Ealing, west London. A Polish au pair fled screaming and reported the matter to the police.
At the Old Bailey in 1987 he was found guilty of the manslaughter, on the grounds of diminished responsibility, of his younger sister at the family home in Hounslow.
After a quarrel, he had knocked her unconscious, strangled her with his hands and then tied telephone flex around her neck. He was sent to the St Bernard's unit at Ealing Hospital, but he was allowed out after just five months.