The clapped-out Chevy had not been moved for days. But before Lisbeth, 15, could scrawl "Wash me" in the dirt, a rainbow shimmer caught her by surprise. The national saint of Mexico - Santa Maria de Guadalupe - manifested her image in the middle of the windscreen, beneath Lisbeth's trembling finger.
Etched in the glass is the Virgin's outline, surrounded by a spiky halo like a cactus. The neighbourhood devout started gathering and then a volunteer popped the windscreen from the jalopy. The excited crowd walked the windscreen solemnly along the highway in pilgrimage for three hours to have it blessed in the basilica last Sunday.
Lisbeth swears to The Independent that two days after they removed it, a message appeared in the glue on the windscreen's edge: "See the orange letters?" Lisbeth says. They read "Liberate and protect those who cannot see me."
Two years ago, when a waterstain in a local underground station took on the Virgin's silhouette, police had to cordon it off after 50 Mexicans a minute came to pray. Eventually the hunk of pavement was prised up and locals built a special chapel for it, just as they intend to do for the windscreen.
The archdiocese has yet to rule on Our Lady of the Windscreen but it declared that "there is no divine presence in these lines formed by a water leak" in the metro .
Inside the Basilica of Guadalupe, the world's second most visited Catholic church after the Vatican, a gold-framed relic takes pride of place: the cloak of the Aztec peasant Juan Diego, where the same dusky virgin took form in 1531.
The Pope is to canonise Juan Diego next spring at the Vatican, despite a controversy that rocked Mexico when a local cleric asserted that the Jesuits faked the image to boost Aztec conversions.