​McLaren’s 2026 title defense hasn’t been primarily derailed by a lack of raw pace, but rather by the explosive fragility of the Mercedes powertrain bolted into the back of the MCL40. Now, the Woking squad is finally getting the hardware they need to stop the bleeding.According to a recent report from Italian F1 insider Giuliano Duchessa, McLaren will arrive at the Belgian Grand Prix armed with the latest, highly anticipated reliability specification of the Mercedes engine, alongside a heavily updated rear wing. More importantly, this Spa update serves as the critical baseline for a “significant” chassis upgrade package slated for Budapest.AdvertisementAdvertisementAdvertisementHere is why this two-step upgrade path could violently shift the midfield and front-running dynamics.To understand how crucial this engine upgrade is for Lando Norris and Oscar Piastri, you have to look at the sheer number of points McLaren has left on the table due to hardware they don’t even build.The 2026 Mercedes power units have been plagued by severe, deeply rooted battery-related failures across the grid. This mechanical flaw triggered DNFs for Mercedes drivers George Russell and Kimi Antonelli, but it hit McLaren even harder, resulting in a catastrophic double-DNS for both Norris and Piastri in China.May 2, 2026; Miami Gardens, FL, USA; McLaren driver Lando Norris (1) during the F1 Miami Grand Prix Sprint Race at Miami International Autodrome. Mandatory Credit: Sam Navarro-Imagn ImagesThe situation became so dire that McLaren Team Principal Andrea Stella recently admitted that being a customer team in 2026 had put them on the “backfoot,” as they lacked the deep factory integration required to quickly solve these complex power unit glitches.AdvertisementAdvertisementAdvertisementNow, the cavalry is finally arriving. McLaren will fit their third Internal Combustion Engine (ICE) of the season at Spa, utilizing specifications introduced by Mercedes AMG High Performance Powertrains specifically to eliminate these exact reliability gremlins.With the powertrain theoretically bulletproofed, McLaren can finally shift their entire focus back to aerodynamic development without worrying about the engine grenading itself mid-race.McLaren Technical Director Neil Houldey confirmed that the team is bringing a new rear wing assembly to Spa to help manage the severe energy deployment demands of the 7-kilometer circuit. However, this is just an appetizer. By securing a reliable mechanical baseline in Belgium, McLaren is clearing the runway to introduce a massive, season-defining chassis package at the Hungarian Grand Prix.If the Mercedes engine holds together, the rest of the grid is about to find out exactly how fast the fully upgraded MCL40 really is.