By Ros Krasny

BOSTON (Reuters) - Tom and Ray Magliozzi, hosts of National Public Radio's popular "Car Talk" program, will retire in September after decades of dispensing automotive repair and driving advice laced with a side of wicked humor.

The pair, in their guise as the self-deprecating Click and Clack, the Tappett Brothers, have been taping the weekly show for WBUR, Boston's public radio affiliate, for 35 years, but say it is time to "stop and smell the cappuccino."

Elder statesman Tom Magliozzi turns 75 this year.

"My brother has always been 'work-averse,'" Ray Magliozzi, 63, said in a statement. "Now, apparently, even the one hour a week is killing him."

NPR will continue to broadcast the show with material curated from the best of the more than 1,200 episodes recorded by the Magliozzis over the years, with occasional updates from the brothers.

Gary Hunter, who helps manage events for the magazines Classic Motorsports and Grassroots Motorsports, said he would miss the program, and that his girlfriend Sally would miss it even more.

"My girlfriend doesn't work on her car; I do," he said. "But she listens to 'Car Talk' on the way to work on Saturday. I'm always amazed that she is totally not into cars but she enjoys their bantering and people calling in and the scenarios."

The brothers urged their fans not to grieve: "Thanks to all for the nice comments, but this isn't a wake! We won't be taping new shows, but we will still be polluting the airwaves!" they said via Twitter.

"Car Talk" was first broadcast in Boston in 1977 and picked up nationally by NPR 10 years later. It is heard weekly by an audience estimated at more than four million listeners on almost 600 stations.

"The early days of Car Talk was a time when dinosaurs roamed the earth and people actually worked on their own cars," the pair quip on their website.

Among the celebrities who have called into the show are broadcaster Morley Safer; actors Ashley Judd and Geena Davis; and astronaut John Grunsfeld, phoning from the Space Shuttle.

At the end of each show, Ray typically warns the audience, "Don't drive like my brother," to which Tom replies, "And don't drive like my brother."

The brothers won a Peabody Award in 1992 for "distinguished achievement and meritorious public service."

Both brothers, veteran car mechanics who operate a garage in Cambridge, graduated from the Massachusetts Institute of Technology. They gave the commencement address to the university in 1999.

The Car Talk offices loom over Harvard Square in Cambridge and is dubbed "Dewey, Cheetham & Howe" after the imaginary law firm featured on the show.

The much-loved broadcast has made its mark on popular culture in the Magliozzi's native Cambridge - referred to on air as "our fair city" - and beyond. The brothers provided the voices for animated cars in the blockbuster 2006 Disney Pixar film "Cars".

"Car Talk: The Musical!", presented by Suffolk University, enjoyed a brief run in Boston in 2011.

As for their fans, they will be making the most of the shows remaining before they retire.

"I'll be listening to their show tomorrow," Hunter said, "because I'll be out in the garage working on my buddy's car."

(Reporting By Ros Krasny, additional reporting by Toni Clarke in Boston; editing by Gunna Dickson and Richard Chang)