Charles Krupa, Associated Press
"Car Talk" hosts/brothers Ray and Tom Magliozzi pose along with their cartoon likenesses.

BOSTON — Tom and Ray Magliozzi, aka Click and Clack, the Tappet Brothers, of NPR's "Car Talk" fame, are just two low-ego lugs. That's why — familiar self-deprecating shtick aside — the boys' ambivalence about their new public television series rings seriously true.

"I hope that people look at it mercifully," says the younger, stockier, talkier Ray (Clack) about "As the Wrench Turns," a half-hour series that wraps social and environmental messages inside an animated sitcom.

Premiering tonight on PBS, the show follows Click and Clack's exploits co-hosting a nationally syndicated radio show and running a car repair shop that mirrors their real-life Good News Garage in Cambridge, Mass. The show will air in two-episode blocks for five weeks.

(It debuts at 7 and 7:30 p.m. on KUED's digital channel 7.2; it airs Saturday at 9 and 9:30 p.m. on Ch. 7.)

But will the humor of "As the Wrench Turns" compare to what we've come to expect from Tom and Ray's hugely popular radio franchise — the most listened-to entertainment program on NPR?

"It's lame enough that people will laugh at some of the lame stuff," Rays says in between bites of lunch on the patio of radio station WBUR-FM in Boston, where the Magliozzis tape "Car Talk." "There will be some chuckles and wry smiles," he says as brother Tom (Click) looks on, cigar-smoking and chortling gently.

Tom and Ray voice their animated selves in the TV series, executive-produced by Howard Grossman. But "As the Wrench Turns" deviates from "Car Talk's" successful format. No phone calls from distressed car owners, no long bouts of brotherly banter, no silly signature "Puzzler" or "Stump the Chump" jokes. Instead, the show plays out like a family-friendly "Family Guy" or "The Simpsons."

Story lines include Click and Clack's loony fundraising efforts for their bankrupt radio network — which involves their joint run for the White House — plus outsourcing their radio show to India and creating the first-ever pasta-fueled motor vehicle.

And unlike their NPR series, which is definitely a two-personality affair, "Wrench" turns on an expanded cast of characters, including oddball auto mechanics Crusty, Fidel and Stash; perky young radio producer Beth; and the brothers' chunky female garage receptionist and bookie, Sal.

"It's cute," says "Car Talk" executive producer Doug Berman, who runs "Car Talk's" parent company called (for real) Dewey, Cheetham & Howe, and has worked with the Magliozzis for more than 20 years. His thoughts mesh so thoroughly with the Magliozzis' that he seems like a third brother.

And he knows his "Wrench," since he wrote nine of the show's 10 episodes.

So how did the Magliozzis get into this prime-time pickle?

"We felt sorry for Howard," Tom says quietly. "He'd been working on it for so long."

An independent producer of telefilms and TV specials, Grossman cold-pitched an idea for an animated show involving actual, taped "Car Talk" phone calls — with little effort from Tom and Ray — to Berman in 2001. The show went through several transformations, multiple network rejections and ever-increasing Berman and Magliozzi involvement before PBS bought the fully scripted version of "Wrench" in 2006.

And the TV-reluctant Tappet Brothers, who swear they would rather sit around drinking coffee and kibitzing, were suddenly ensnared in their very own sitcom. The Magliozzis had done very little voice-over work before. But they "were one-take wonders," Grossman says.

And animation seemed the perfect solution to another dilemma. Radio stars that they are, Tom and Ray are hardly Hollywood-suave. Like homely Garrison Keillor of "A Prairie Home Companion," and Bob Elliott and Ray Goulding, the dry-witted radio duo who sporadically dipped their toes in television from the 1950s into the '80s, the Magliozzis do not have majorly telegenic mugs.

It's their voices — Ray's sharp Boston accent and Tom's rich laugh — that compel.

"They are the first to admit that they have the perfect faces for radio," says John F.Wilson, senior vice president and chief TV programming executive for PBS. "If you think about some of your favorite animated characters, there's always a great voice underneath them," Wilson says.

Still, despite their mugly countenances, Tom and Ray have done their share of live-action TV, from stints on newsmagazines "60 Minutes" and "20/20" to a gig discussing the car of the future on the PBS science series, "Nova."

"All of those, whether they're live or live-on-tape, are a pain," Ray says. "In our experience it takes eight times longer to do TV than it does radio. So this is not a career move," he says of "Wrench." "We have no aspirations. Let me make that clear."