Vito Joseph (Pop) DiLoreta, 71, who had worked as a welder for Metro and its predecessors for 41 years before its retirement in 1975, died Friday at his home in Alexandria after a heart attack.

For the last five years, he had been a part-time security guard with Watergate at Landmark in Alexandria.

Mr. DiLoreta was born in Princeton, N.J. He came to Washington as a young man and worked as a welder on streetcars for the old D.C. Transit Co. and later for the D.C. Transit System and Metro. He worked on buses after streetcars were discontinued.

A resident of Alexandria for more than 45 years, Mr. DiLoreta was a member of the Woodbridge Moose Lodge.

His first wife, Josephine H. died in 1972.

He is survived by his wife, the former Evelyn Carver of Alexandria; a son, William N., and a daughter, Gloria J. Caporaletti, both of Alexandria; two stepchildren, Timothy H. Carver of Dumphries, and Diana C.Moore of Blacksburg, Va.; a brother, Ralph Loreta of Vineland, N.J.; five sisters, Mary Celia of Bethesda, and Rose Procopia, Ginny Dougherty, Millie Del Collo and Georgianna Salizzo, all of Vineland, and six grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the cardiac and cancer unit at Children's Hospital National Medical Center of Washington.