General Motors Corp. revamps the troublesome retractable hardtop on its Pontiac G6 convertible ahead of a production re-start for the tepid-selling model later this month.

Sources tell Ward’s the auto maker’s supplier, Karmann GmbH subsidiary Karmann USA, made the fix late last year and GM shipped several units with a more robust retractable top to dealers. The fix focused on a panel-to-panel latch on the 2-piece clamshell lid, which folds into the trunk.

GM is “perfectly happy with where it’s at now,” the source tells Ward’s. “The fix virtually eliminates the squeak-and-rattle issues.”

GM confirms recent work on locking pins within the latch mechanism but characterizes the changes as continuous improvement. “Nothing major,” a spokesman says. “We’re always tinkering, as you might with any product.”

The spokesman also confirms suspension of G6 convertible production at the model line’s plant in Orion Twp., MI, in recent months to accommodate the addition of the redesigned ’08 Chevrolet Malibu, which GM launched in October.

GM builds the Malibu in Fairfax, KS, but Orion serves as a flex-link site, which allows the auto maker to dial production up and down according to demand. And demand for the midsize sedan has been brisk. Malibu sales shortly after launch in November were three times what GM expected, and dealers continue to tell Ward’s of extremely short supplies three months later.

The spokesman also says GM used downtime on the G6 convertible to fully integrate its production with the sedan and coupe variants. GM previously produced the convertible on the same line as the sedan and coupe but moved it off-line to install the roof system.

“Naturally, we chose the winter months,” the spokesman says. “That’s when you have lighter demand.”

A joint venture between Karmann USA and Southgate, MI-based ASC Inc. won the original contract to supply GM with the roof, as part of a deal that first called for production of a retractable system for the now-defunct Chevrolet SSR convertible pickup. Karmann would perform the hard-core engineering work and ASC would build the units. However, the JV dissolved before the 2006 production launch and Karmann took over sole development of the G6 system.

Durability issues stymied the supplier, and GM was forced to delay the convertible’s launch by several months. Since its debut in spring 2006 as a ’07 model, buyers have complained of squeaks and rattles, despite GM’s quality-assurance efforts, such as building the roof unit outside of the assembly plant. Karmann ships the roof as a module from its facility in Plymouth, MI, to Orion.

But some owners still question the folding top’s quality. One Internet chat room for enthusiasts takes the convertible to task, complaining of multiple trips to the dealer for lengthy fixes. One poster goes so far as to advise others to keep a detailed log of service in case they decide to pursue a buy-back.

A separate source with knowledge of the convertible’s development blames poor product planning, telling Ward’s the retractable-roof on the G6 was tantamount to afterthought.

“The G6 wasn’t really designed for it,” the source says.

Given the quality issues, its late launch and rumors of lukewarm sales, the convertible’s future comes into question, especially as auto makers enter what could be an unfriendly market for droptops in 2008.

Erich Merkle, an analyst and vice president-forecasting at IRN Inc., says it wouldn’t come as a surprise to him if GM discontinued the G6 convertible.

“It’s been a nightmare to build, and sales haven’t been that great,” says Merkle. “The price point might be a little high. I like the idea of a retractable hardtop – you can have a convertible year-round in a winter climate – but people in the U.S. aren’t willing to pay for them like they are in Europe.”

Pricing for an ’08 G6 GT convertible starts at $30,045 and includes a 3.5L V-6 engine mated to a 4-speed automatic transmission. Most retractable roofs similar to the system on the G6 appear on higher-priced luxury vehicles.

GM does not break out convertible sales from its monthly results. But according to Ward’s data, in its first full model year the car accounted for 13% of ’07 Pontiac G6 output, or 22,065 units from a slate of 164,374 builds. Last year, G6 model line sales fell 4.8% to 150,001 units, from 157,644 in like-2006.

Related document: U.S. Sales of Cars by Model, 2003-2007

The GM spokesman says the auto maker has been pleased with G6 convertible sales and according to the company’s data, there is nothing to suggest softening demand that is inconsistent with 2007’s overall market downturn.

Jeff Miller, a sales manager at Lynch Buick-Pontiac in Manchester, CT, recently told Ward’s he had not heard any news on the G6 convertible’s future, calling it “a good seller for us. That might be a regional thing, too,” he says.

Jack Fish, a sales manager at Howard Buick-Pontiac-GMC in Elmhurst, IL, sold a Pontiac G6 the very day Ward’s called to inquire about the car. But, he adds, “It was the first one in a long time.”

Would-be buyers are not “beating the door down to get one,” Fish says, adding the car sold “very well” at launch.

“I believe it’s a little over-priced, and the economy isn’t where it needs to be,” he says. “And this is a car people can do without.”

Global Insight analyst Rebecca Lindland says convertible sales tend to move in lock-step with the economy. And with rumblings of a recession, this year may not be a healthy market for the vehicles, she adds. “This isn’t the time for flashy, fun cars,” Lindland says.

Among other convertibles, the Chrysler Sebring, has ranked as the best-selling convertible in the U.S. over the last 10 years. Chrysler added a retractable hardtop to a pair of available soft-top models in ’08 and sold 21,599 units over a 9-month period in 2007 with the car’s new-generation platform.

Sales peaked at 41,883 units in 2003, according to Ward’s data.

The Volkswagen Eos, which like the G6 comes available with a retractable hardtop only, sold 11,973 units in 2007, also its first full year.

Jill Lajdziak, general manager for GM’s Saturn division, believes convertible sales will hold up fine in 2008. Saturn’s portfolio includes the Sky roadster, a soft-top convertible with razor-thin availability until seasonality softened demand in the final two months of 2007.

“So far, it’s generally been the toy in the garage,” Lajdziak told Ward’s during an interview at last month’s North American International Auto Show in Detroit. “The people that can afford a toy generally aren’t affected as much by the economy.

“We’ll see how it plays out,” she added. “We’re monitoring production very closely. We don’t want to get into a position where we have too much inventory.”

However convertible sales shake out this year, Lindland thinks GM should stick with the G6 retractable, if only as proof that a company known for its pickups and SUVs also builds desirable passenger cars.

“Part of it is managing your expectations,” she says. “You’re not going to sell 100,000 units in the segment. GM needs to show patience.”

Chris Theodore, ASC vice chairman, claims the market for convertibles is growing. But, he adds, it’s also splintering.

“Interest in roof systems is growing in some respects,” he tells Ward’s. “We just launched, with Chrysler (LLC) the SkySlider on the Jeep Liberty. That thing’s going crazy. We’re right at the capacity limits right now.”

Theodore characterizes roof systems as the last frontier where auto makers can significantly differentiate their products. Premium interiors, functional seating systems, high-tech infotainment, and ride and handling all rank as areas already thoroughly mined, he says.

“The last thing that’s left is roof systems. People like the feeling of open air and the ability to see more of their surroundings. Multi-panel panoramic roofs are growing by leaps and bounds,” Theodore says, adding that retractable hardtops may not become as pervasive as many in the industry predicted a few years ago.”

“When you get into the other side of convertibles and retractables, what you’re honestly seeing is the pendulum finding the balancing point between convertibles and retractables,” he says.

Nevertheless, GM product boss Bob Lutz says he is no fan of retractables – styling or otherwise. “They look funny,” he tells Ward’s during a recent product preview in Phoenix. “And you will never engineer all the squeaks and rattles out. We’re going to see a day soon when people go back to fabric tops entirely.”

But, that doesn’t mean the G6 convertible will go away anytime soon, he adds. “The G6 convertible is in no danger.”

– With Eric Mayne