Team boss Andreas Seidl says McLaren "never considered" building its own Formula 1 engine.
After 2020, the British team will continue its push to catch the top three teams by switching from customer Renault to customer Mercedes power.
'Never a topic'
However, McLaren supremo Zak Brown had said last year: "It is possible, but not very likely, that we will have our own engine in 2021."
READ | McLaren to remain 'independent' - Seidl
But Seidl, the former Porsche sports car boss who started working at McLaren in May, told Speed Week: "This was never seriously considered.
"You'd have to invest a lot of money. Additionally, you'd also need plenty of time to catch up with what the current manufacturers have already learned.
"For those two reasons, it was never a topic for us," Seidl added.
1998 and 1999 world champion Mika Hakkinen thinks Seidl's decision to reunite McLaren and Mercedes is right.
"It is a partnership that worked very well in the past, and Andreas Seidl has identified this as being a key element in McLaren's strategy to become winners again," he told his Unibet column.