Citing one of their favorite programs, members of the Federal Communications Commission yesterday imposed a $5,000 fine on radio station WMAL for airing commercials that run longer than indicated by station records.

All the voting members praised the "Hardin and Weaver Show," the station's popular morning music and talk program, but still voted 5-1 to levy the fine.

Commissioner Abbott M. Washburn declared that the show should be given an award "for making ads palatable."

Commissioner Margila White said she couldn't see how it was possible to separate the advertising and jokes on the show.

Station officials made the same argument, saying it was difficult to determine where the commercials end and the entertainment begins because Frank Hardin and Jackson Weaver joke throughout the entire show.

However, Arthur L. Ginsburg, chief of the FCC's complaints and compliance division, said failure to fine WMAL the same as other rulebreakers would make his job impossible in the future.

Commissioner Robert E. Lee, the lone dissenter, wanted only to send a letter of admonition.

WMAL has 30 days in which to contest the fine. A spokesman said it was up to the New York headquarters to decide whether to accept the decision or appeal.