Thomas L. Imbesi, who retired about 10 years ago as vice president of the 7Up Bottling Co. of Baltimore, died Tuesday of heart failure at St. Joseph Hospital. He was 79 and a resident of Eldersburg for many years.

A Mass of Christian burial for Mr. Imbesi was being offered today at St. William of York Roman Catholic Church, Edmondson Avenue and Cooks Lane.

He had opened the Baltimore plant, one of several 7Up bottling operations owned by members of his family, in 1936.

His wife, the former Margaret Castellano, died in 1981.

He is survived by two sons, Joseph A. Imbesi of Hunt Valley and Dennis M. Imbesi of Columbia; a daughter, Clara I. Morrison of Bonsall, Calif.; three sisters, Mary Carella, Catherine Mazzola and Millie Lorusso, all of Philadelphia; and two grandchildren.