While the majority of headlines regarding the use of engines beyond the eight allowed per car this season have centred on Red Bull world title contenders Mark Webber and Sebastian Vettel, BMW Sauber has also been totting up enough failures to put it in line for possible penalties.

Under new rules introduced for the 2009 season, each car - regardless of who is driving it - is limited to just eight new engines, requiring teams to carefully manage where it runs each unit and where it chooses to introduce fresh ones, but some are now finding that reliability problems are beginning to cause new headaches. Much has been made about RBR's challenge being threatened by recent failures for both Vettel and Webber, but BMW Sauber's Mario Theissen confirmed on Friday that both Nick Heidfeld and Robert Kubica could face ten-place grid penalties before the end of the campaign.

"We are borderline after the two unexpected engine failures - fresh engine failures - we had recently," Theissen confessed, referring to the qualifying problems his line-up sustained at Monza, "We have one fresh engine for each car for the final four races and, apparently, we have never done four races with one engine on the track [although], on the dyno, it would work. We have to see now where we are.

"Apparently, we have some mileage left on used engines to cover the Fridays, but it will be tight. We are not sure if we will get to Abu Dhabi with this engine, so we will see. Maybe we will have to pull a ninth engine."

While BMW Sauber and Red Bull, which runs Renault engines, will be keeping fingers firmly crossed for the championship run-in, points leaders Brawn and the resurgent McLaren and Force India appear to be in better health, with Mercedes' Norbert Haug confirming that the Three Pointed Star's supply is looking strong, despite having to supply three teams.

"We are fine so far," the burly German assured, "I hope it stays like that but, as my colleagues already pointed out, [failures] can happen very quickly - if you have one small problem, it will happen. I think it is absolutely important not to get complacent and have respect in front of the work you have to do. So far so good, and I would say thank you to the guys in Brixsworth and Stuttgart. They did a fantastic job so far but, again, it is still quite a way to go and I hope we can continue this trend."

Williams' Sam Michael and Ferrari's Stefano Domenicali also reported few problems, although both shared Haug's acknowledgement that failures could happen at the most unexpected moments.

From our point of view, it is quite okay," Michael confirmed, "We have not had any failures so far this year, so we are managing our pool of eight between each driver and, so far, we are on schedule not to use any new engines.

"That can always change in the next few practice or race sessions but, at this stage, it has worked out well. It is a manageable thing - you can handle probably one failure but, once you get more than one, it becomes very tricky. You either have to reduce practice mileage or fit a new engine, but we are fine."

"We have two engines for the next four races for each driver, but I can really cut and paste what Norbert and Sam said," Domenicali added, "You cannot be complacent, but this is the situation now and we need to see how the situation will evolve."