He doesn’t manage to repair the car.
It should have been expected, really, for such a rundown car to be nonfunctional. After a few rough smacks to the engine, Yang Rong had proceeded to channel all strength into his kicks, desperately hoping that a miracle would occur. Noah should have also expected that the man intends to solve everything via brute strength – after three kicks, Yang Rong had pulled out a knife and started disassembling the entire thing.
It isn’t so much a disassembly as it is a 'destruction,' the knife being used to pry off the cover, the gasket, the pulleys, everything down to the last screw – Noah wasn’t even aware that there were so many miscellaneous parts.