In front of the weekend’s first race in Bahrain it appeared that Sainz would have to move onto his second MGU K following the early failure he suffered from the race at Melbourne.
In addition to the new MGUK, Sainz switches into a second internal combustion engine, turbocharger and also MGU-H of the season.
Passengers are allowed to use two MGU-Ks annually and three of the other components McLaren has shifted for Sainz in Bahrain.
If drivers want more components beyond those constraints, they will incur grid fees.
It is not yet known if the parts McLaren have shifted can be repaired and added back into the pool of useable components, or if Sainz has just taken a big step towards a grid drop later this year.
On Thursday, Sainz highlighted the weakness of the MGUK, which have been problematic during pre-season.
“It is true we had a couple of failures during testing, so it is something that is just really a weak point of the car,” he explained.
“We will need to continue taking care of to ensure we do not throw any longer things in to the bin because we did throw a couple of them in Australia.”
The remaining portion of the grid is yet to create any power unit element changes so far this year.