Reports claim Renault's top brass have told Red Bull officials they no longer want to supply them after next season.
The Milton-Keynes based outfit have used Renault engines since 2007 with the partnership proving very successful during quadruple world champion Sebastian Vettel's reign at the top.
Although the split has not been officially confirmed, Formula One insiders say the divorce is almost certain - leaving Red Bull to run Honda power units in 2019.
Junior team Toro Rosso's switch to Honda is to be confirmed on Friday.
McLaren are switching from Honda engines to Renault for the next three seasons and their long-expected deal with the French manufacturer is also set to be announced on Friday.
Renault are expected to confirm that they have signed Toro Rosso driver Carlos Sainz for 2018.
He will replace Englishman Jolyon Palmer as team-mate to German Nico Hulkenberg.