As the Cadillacs maintained their strong position at the head of the field, the problems started to mount for Acura when running repairs were required for the No.6 Team Penske.
Juan Pablo Montoya – already a lap down – came into the pits and took on a new nose, leaving him over half a minute adrift of the No.55 Mazda Team Joest running in fifth. Harry Tinknell spent much of his stint trying to avoid going a lap down himself in the No.55, with leader Kamui Kobayashi filling his mirrors with the No.10 Wayne Taylor Racing Cadillac for a number of laps.
The No.10 is continuing to eke out an extra lap or two from each stint compared to its rivals and appears comfortable at this point, sitting 10 seconds clear of the No.5 JDC Miller car and a similar margin ahead of the No.31 Action Express that is now being driven by Mike Conway.
In LMP2, PR1 remains at the head of the class but Simon Trummer has Ben Hanley chasing him down in the No.81 Dragonspeed entry, with the gap now below a minute.
Elsewhere in that category, the No.8 car has been suffering with porpoising issues, leading the team to think something may have broken on the floor. After a lengthy stop in the pit lane with the nose off, the decision was eventually made to take it back to the garage to fix it, dropping it 16 laps off the lead.
The fight at the front of GTLM picked up again with 10 hours remaining when the No.24 BMW’s lead was cut to less than five seconds by the No.912 Porsche; Earl Bamber making progress before handing over to Mathieu Jaminet. The No.911 car also moved forwards, taking over third place from the No.3 Corvette during a pit stop cycle with the pair now running nose-to-tail.
Risi remains in touch in the No.62 Ferrari, Daniel Serra running within six seconds of Garcia with a little over half a minute covering the top five.
GTD is still led by Lamborghinis, although the No.9 Pfaff Porsche briefly hit the front before Lars Kern handed over driving duties to Dennis Olsen. That put the No.44 GRT Magnus back in the lead ahead of Corey Lewis in the No.48 Paul Miller Motorsports car.
Further down in GTD, in a potentially similar issue to the No.8 LMP2 car, a broken splitter on the No.86 Meyer Shank Racing Acura forced it behind the wall and cost it a number of laps.
There has been little in the way of on-track incidents over the past few hours, despite teams having to deal with temperatures dropping and cold conditions impacting on car handling.