Montoya not to blame for engine failure

Montoya's team mate Ralf Schumacher took his third victory of the year after the Colombian's demise, then alluded that it was because he put less stress on his machinery.

"Going into the race we knew it was going to be tight for the engine," he explained. "Juan Pablo pulled away and I thought, 'you do what you want'. I had started to save the engine already, because I know how long and hard this race is. And it paid off in the end."

But Williams technical director Patrick Head has defended Montoya's press-on style, while BMW Motorsport technical director Mario Theissen surmised that two starts and a lengthy pitstop caused by a refuelling rig fault were more likely culprits for the engine's premature demise. Temperatures in Hockenheim nudged 30 degrees celsius, putting extra strain on the already highly-stressed engines.

"The engine temperatures go to the limit here, but normally it should be capable of standing a long pit stop," said Theissen. "We focussed on Ralf after the car was out and didn't focus on the engine. We will take it to Munich tonight (Sunday) and open it tomorrow morning, so by lunchtime we should know what happened.

"But we saw many cars retiring with engine problems today," he added. "Certainly it was stressful to have the restart because the engines ran hot twice. This allied to the 30 seconds he was stationary in the pits, sending the temperatures up again, might be an explanation."

With no cooling fans, a Formula 1 car needs to be moving to push air through its radiators. Although cars are stationary on the grid for several seconds before the start, this is normally following a period of relatively unstressed running. In a pit stop, however, the engines have been operating at near-maximum stresses for a long period of time and there is a large amount of heat that needs to be dissipated. Hockenheim is especially stressful, with engines on maximum revs for over half the lap.

The team attempted to refuel Montoya with his own rig, but switched to Schumacher's when it appeared that fuel was not flowing. However, Head says this was not actually the case and that in the end, the car's tank was actually over-filled.

"The indications were all suggesting that the rig had stopped flowing," explained Head. "The lights that come on down by the nozzle went off, but it looks as if the rig was actually pumping, so as it turns out we put far too much fuel in the car anyway. Thinking he hadn't got enough fuel, we actually swapped the rigs over and used Ralf's rig. We had enough fuel in each rig to refuel both cars, so it was no problem recalibrating Ralf's rig before his stop."