Germany's Auto Motor und Sport says David Coulthard's move into that country's DTM touring car series with Mercedes-Benz may have been thwarted by the faltering relationship between Mercedes and Red Bull.
Coulthard, who retired from Red Bull's F1 team last year and remains an adviser to the team, had been tipped to drive a year-old Mercedes in the series this year with Red Bull backing, but the German sports newspaper says Red Bull boss Dietrich Mateschitz is unhappy about Mercedes' new deal to promote rival Monster energy drink in F1. Tensions between the two companies began over the winter, when Red Bull Racing reportedly tried to swap its Renault engine deal for Mercedes powerplants, but was rebuffed.