 McLaren deliberately introduced two brand-new engines for both Alonso and Button at the Belgian Grand Prix, effectively moving them to the back of the grid, but allowing them to contest the Italian and Singapore Grands Prix — deemed to be crucial races in assessing the engine's development — without the risk of a penalty. Despite this plan, the team were forced to take another penalty in Italy when further engine changes were needed, bringing their total use up to nine engines from the original allocation of four. Belgium also saw the team's second major aerodynamic update: the team added extra fins to the front of the floor to improve air flow under the car, lowered the height of the sidepods and revised the engine cover. The position of the radiator used to cool the energy recovery system was also changed. Both cars completed the Belgian Grand Prix, but once again finished outside the points, one lap down in thirteenth and fourteenth place. Button described the result as "embarrassing" after both cars were classified as finishing behind Sebastian Vettel despite Vettel retiring from the race on the final lap. The team reverted to the longer-specification snub nose for the Italian Grand Prix in order to provide better aerodynamic balance and lower drag on the high-speed Autodromo Nazionale Monza circuit. The change proved to be of little benefit, as both drivers were eliminated in the first qualifying period and struggled throughout the race. Button finished in fourteenth, while Alonso retired with an electrical problem but was classified in eighteenth position as he had completed 90 % of race winner Lewis Hamilton's race distance. The race marked a milestone of fifty races since McLaren's last Grand Prix win at the 2012 Brazilian Grand Prix.
