Tippett Studios, which created the fantasy world in Jurassic Park, now helps Buick's Encore dodge dinosaurs in a new ad campaign.

General Motors’ marketing operations are a step short of chaos, according to sources close to the maker, with two of GM’s most important brands set to review – and likely make major changes to – their ad agency partnerships.

Chevrolet is the latest to be looking for new talent after a disappointing effort to turn to an unusual partnership between two of the advertising industry’s largest agencies. The largest of the GM brands is also getting a new global marketing chief of its own next month. As TheDetroitBureau.com previously reported, Cadillac also is switching ad agencies.

The reported moves mean that the legacy of former GM global marketing czar Joel Ewanick is largely “gone,” according to an industry veteran. Ironically, it appears that the latest shake-up involves a game of musical chairs, some of the agencies coming back to GM having had long associations with the maker in the past.

That notably includes Campbell-Ewald, the Michigan firm that was Chevrolet’s agency of record for more than seven decades before being unceremoniously dumped by Ewanick. CE is now expected to take over the Cadillac account, however, and has gone so far as abandoning its long-time suburban Detroit home for new offices around the corner from GM’s Detroit riverfront headquarters.

“Obviously, dealers and consumers have not responded to the latest GM advertising,” says Marty Bernstein, an ad industry veteran and regular columnist for TheDetroitBureau.com.  Chevy’s latest campaign, dubbed “Find New Roads” may be finding “some resonance,” according to Bernstein, but it landed “after the party was already over.”

Chevy’s marketing  was shifted to a new entity called Commonwealth early last year, an unusual 50/50 partnership pairing San Francisco-based Goodby, Silverstein & Partners with New York’s McCann Erickson Worldgroup. The results have apparently shown the difficulty of getting two rivals to cooperate, according to some sources, for the good of their client.

Chevy clearly wasn’t gaining traction when it needed it, the maker – and GM on the whole – losing market share last year.

In the end, however, the Commonwealth plan may have been doomed by backlash to the extensive changes wrought by Ewanick during his hard-charging rein as General Motors’ Chief Marketing Officer – before being unceremoniously dumped last summer.  Ewanick not only cut Campbell-Ewald’s long-running ties to Chevy but pulled GM out of the Super Bowl and even dissed on Facebook just prior to that social media giant’s disastrous IPO.

“Ewanick’s legacy is gone,” concludes Bernstein, suggesting “They didn’t like a lot of what he had done.”

While GM has yet to confirm its plans, Campbell-Ewald’s old brand, Chevrolet, will now work exclusively with McCann Erickson – and in this often incestuous business, that agency used to hold the account for GM’s Buick and GMC brands.  (McCann also served Saab at one point.)

The changes don’t appear to be over.  Tim Mahoney, recently of Volkswagen and before that Subaru, will report for work on April 1 as Chevrolet’s global marketing chief.  Key questions will be whether he restores the severed ties with the NFL – or with Facebook which has made it clear it would like GM ad dollars back.

But also uncertain is whether the GM regime will let things rest at Buick GMC.  The car side of that pairing today revealed a new ad campaign featuring the new Encore crossover nimbly dodging under the feet of a roving dinosaur.

Whether that account also gets puts up for review could depend on the success of this campaign, observers caution.