JFK reportedly drove a black Cadillac convertible coupe while he was auditing classes for a semester at Stanford. He was reminded of this
by the owner of Boaz Auto and Glass located at the corner of El Camino Real and Embarcadero in Palo Alto when he wrote Kennedy in July, 1962.
In the letter, Boaz recalled the day Kennedy was leaving California that he pulled into the station and asked Boaz to fill it with gas and perform any other maintenance that would be needed for a cross-country drive. When the work was finished, Jack (who was always short of cash) gave Boaz a blank check and trusted him to fill in the honest amount of the work.
[JFKL]