for LIVE text commentary
The #7 Toyota continues to hold sway out front as the 20134 Le Mans 24 Hours reached its half-way point, but the #1 Audi has hit trouble.
After a long second stint in the car, Alex Wurz handed over to Stephane Sarrazin during the hour and though the Frenchman has lost time to Andre Lotterer in the following #2 Audi, the lead remains comfortable at almost two minutes.
However, there was bad news for the #1 Audi, which had been running a solid third and on the lead lap when it completed a very slow lap having just come out of the pit-lane. Returning to the pits, the car has been wheeled into the garage as mechanics pore over it.
It is now set to lose third place to the #20 Porsche, which had been running in a lonely fourth place two laps behind the closest rival before the #1 Audi's unexpected problem.
The #14 Porsche also has a chance to make up a place depending on the severity of the issue, Marc Lieb currently four laps behind. Meanwhile, the #8 Toyota – on track with Sebastien Buemi at the wheel now – is up to sixth place, but 12 laps off the lead having been forced to make an unscheduled stop in an effort to cure balance issues.
In LMP2, the #35 OAK Ligier continues to stretch its advantage, Alex Brundle managing the car's fastest lap of the race during the hour to put almost a minute and a half between himself and Paul-Loup Chatin in the Signatech Alpine.
The lead battle in LMGTE Pro remains the closest on track at the moment, though Aston Martin's Bruno Senna has now shaken off the advances of Corvette and Ferrari, with the latter now ahead of its American rival having jumped them during the pit-stops.
In LM GTE Am, Aston Martin holds the lead with its all-Danish driver line-up, with the second place SMP Ferrari more than two minutes behind.
for live text commentary
full updates after each hour
Live text commentary recap of Hour 12: Key moments in bold
Kristensen is in trouble in the #1 Audi! Going very slowly on the Mulsanne straight, he's going through 'power cycles' to try and fix the issue
Senna pits the lead #97 Aston Martin in the GTE PRO class, while the #1 Audi appears to be going slowly out on track...
Now Milner pits the #74 Corvette and hands over to Westbrook but Ferrari has got the undercut and Fisichella is ahead! That's P2 in the GTE PRO class for the #51 car
The #1 Audi is now 1m08s behind the #2 Audi which is a very good recovery effort following Duval's crash and the rebuild job. The top three all on the same lap after very nearly 12 hours of racing
As we near the half-way point in this race, the lead Toyota has now completed 184 laps and is 2mins ahead of the #2 Audi
Having fallen away in his battle with Milner, Vilander pits the #51 Ferrari from third in the class. He is handing over to Giancarlo Fisichella
The LM GTE Pro fight continues, with Milner busy keeping Vilander behind him, while Senna extends his lead to 12secs further up the road
The top three are all lapping at roughly the same pace as they settle into the darkness... the light should start returning in this part of the world around 4.30am
Nicolas Prost is back out in the #12 Rebellion, but is down to 12th overall now
The #12 Rebellion is in the pit-lane again and seems to have been there for a little while... the car has made 20 pit stops so far!
Corvette's Milner has slipped behind Senna's Aston Martin in the fight for the GTE Pro lead and is now fending off Vilander in the AF Corse Ferrari again
It's running 13 laps down on the LMP2 leader, but the #27 SMP Oreca is set to lose more time after being handed a 45secs stop-go for speeding in the pit lane
The #14 Porsche is in the pit lane, with Marc Lieb taking over from Neel Jani
It's not quite the fastest lap of the class in this race though - JOTA have gone an iota faster...
Somewhat out of the blue, the LMP2 leading #35 OAK Ligier has just put in its fastest lap of the race, courtesy of Alex Brundle
Sarrazin is in the car now in place of Wurz
As it has done almost the entire race, the #7 Toyota responds by coming straight in after its closest (but still very distant) rival
The #2 Audi comes in for its 14th stop as well now. Lotterer stays in the car
The #1 Audi pits to take its 14th stop of the race so far