McLaren say Lando Norris' retirement at the Dutch Grand Prix was purely a chassis issue, not a power unit one - however say they have run full checks on the engine too.
Norris' late retirement in Zandvoort cost him a haul of 18 points in his championship fight against teammate Oscar Piastri.
The Papaya driver said he smelt smoke coming from the cockpit of his car while running in second place before rather immediately stopping on track.
It was expected that the Mercedes power unit was to blame for the abrupt end, but Andrea Stella & Co have confirmed it was in fact a chassis problem.
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According to F1's Lawrence Barretto, the chassis issue has be "rectified" going into the Italian Grand Prix, while the Mercedes engine is still being checked.
It is expected that the unit will be fine to be reentered again as an option for the team, after it supposedly went into "protection mode" when Norris alerted the team of issues.
Barretto said: "Regarding power units for this weekend, both Norris and Piastri will have engine changes (these were always part of the plan and not a reaction to what happened last weekend) - with no penalties triggered."
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