Lando Norris reveals cause of Monaco Grand Prix retirement

Lando Norris has revealed that his retirement from the Monaco Grand Prix was caused by a power unit issue, which ultimately struck without any warning.

The reigning world champion started eighth and spent the opening stages of the race behind Alpine's Pierre Gasly, while nursing an engine problem almost from the outset.

Norris reported power unit concerns to McLaren from the beginning of the grand prix at the Circuit de Monaco, with the issue persisting until it eventually forced his retirement.

It marked back-to-back power unit-related retirements for Norris, who also failed to finish the Canadian Grand Prix.

Asked how much warning he had of the issue becoming terminal, Norris told select media, including RacingNews365: "Not a lot. At the end, it pretty much went immediately.

"There were some issues at the beginning, and then more in the middle, and I don't know if they're related or not. We had to retire the car, so there's not a lot I can do nowadays."

Norris reported strange noises coming from his power unit prior to his retirement on lap 45, with McLaren's attempted mid-race fix actually worsening the issue.

As a result, McLaren reverted the change it believed would solve the problem, leaving Norris to simply live with the issue until it eventually gave way.

Regarding the noises coming from the engine, Norris explained: "Yeah, there was just a lot of stuff I could hear from the engine, the turbo, the battery — a lot of things that didn't sound correct.

"We tried to fix it, but it made the problem worse. We put it back, so I had the problems again, but it seemed we just had to live with it, and then in the end [we retired]."