A caution early in the 19th hour brought drama at the Rolex 24 as a penalty for the previously-leading No. 10 Wayne Taylor Racing Cadillac flipped the race for outright victory on its head.
The action was triggered by a further problem for the No. 74 Riley Motorsports AMG, having previously stopped in the pit lane with what was diagnosed as an electrical issue. Back out on track, Felipe Fraga then suffered a massive lock-up at the West Horseshoe with more apparent electrical problems, and when he couldn’t get moving again it resulted in a full course yellow.
The interruption brought to an end 280 consecutive laps of green flag running stretching 7h48m, but also saw an error for Ryan Briscoe in the No. 10. Briscoe pit under caution but missed the red light at the pit exit and was handed a stop +60s penalty. Wayne Taylor Racing told him to deliver three quick laps before taking the penalty, but Briscoe emerged directly behind new leader Loic Duval in the No. 5 JDC Miller car to go a full lap down.
Briscoe sits between Duval and second-placed Oliver Pla in the No. 77 Mazda Team Joest on track, but now has just five hours to try and close a gap of nearly 100 seconds. His first target will be to get back on the lead lap in case of further cautions, but Duval knows the importance of keeping the No. 10 at bay.
Towards the end of the hour there was further problems in DPi as the No. 31 Action Express Cadillac went behind the wall.
The FCY did bring the LMP2 leaders a lap closer together, with Harrison Newey in the No. 81 DragonSpeed entry now two laps ahead of Ben Keating in the No. 52 PR1.
More significantly it also bunched up the GTLM battle that had threatened to go quiet, with the two Porsches — No. 912 leading No. 911 — seeing their lead cut and the No. 24 BMW coming back into the frame. With five hours remaining, the top four GTLM cars are covered by 13 seconds, with the No. 3 Corvette at the back of the queue.
The caution almost caught out the lead car in GTD, but the No. 48 Paul Miller Motorsports just managed to get into the pits before they closed under caution. After a driver change and work on the brakes, Corey Lewis got back in but was overtaken by Dries Vanthoor in the No. 88 WRT Audi around the outside of Turn 1.
The hour ended under caution again — likely to mix up the race once more — as the No. 19 GEAR Racing Lamborghini returned after a long spell in the pits but Christina Nielsen had to take rapid action to jump out of the car as it caught fire exiting the Bus Stop. The Dane reacted quickly to turn off the electronics and deploy the fire extinguisher with the car ablaze on the apron.