Green’s Dictionary of Slang

(US) a Cadillac El Dorado.

1970		E.K. Walker ‘Harlem Transfer’ in King Black Short Story Anthol. (1972) 48: He saw the Dapper Dude [...] walk coolly over to his El D.
1976		M. Braly False Starts 301: I bought myself [...] a big dark-blue Eldo.
1980		E. Folb Runnin’ Down Some Lines 112: Some kinda Cadillac – El D., D.V., whatever – long and sleeky lookin’, black blade wid a rag top.
1986		J. Ellroy Silent Terror 145: ‘I was patrolling south of here this morning, saw this '79 Caddy Eldo’.
1993		Snoop Doggy Dogg ‘Murder was the Case’ 🎵 I bought my momma a Benz, my Boo-Boo a Jag And now I’m rollin in a nine-trizzay El Do-Rad.
1997		(con. 1970s) G. Pelecanos King Suckerman (1998) 60: Hey, check out that El D! There was a nice baby blue El Dorado riding right beside them.
2006		G. Pelecanos Night Gardener 126: That ain’t no Caddy [...] A Seventy-four El-D is a Cadillac.
2012		G. Pelecanos (con. 1972) What It Was 128: That’s a nice El D, Two-Tone.