Former Williams chief engineer Mark Gillan believes McLaren will not find a quick fix to their MP4-28's problems.
McLaren began this season off the pace and have yet to even come close to the podium never mind challenge for a race victory.
Such is the magnitude of the team's woes that Martin Whitmarsh has been bombarded with questions about whether McLaren would consider reverting to last year's car.
For now, though, the team boss says the Woking outfit will continue with this year's car in the belief that they can find a solution.
Gillan, however, reckons that could take time.
"I was surprised at how slow they were at the beginning of the season," he told the JA on F1 podcast. "They've had a couple of poor starts, but typically get it sorted.
"The fact they are obviously concerned about the development and how quickly they can improve things probably means the problems are down to suspension and the pick up points into the chassis which are quite difficult to change quickly.
"If it was just purely aerodynamic changes, I'd expect them to deal with it within a race or two, so it's probably going to take them quite a while."