PARIS, France - Rumours about troubled Formula 1 engine supplier Renault continue to swirl.The French automaker had a bad 2014 Austrian GP, beginning with paddock rumours of a split with Red Bull, worsened by another failure for Red Bull driver Sebastian Vetteland ending with a stinging rebuke from Christian Horner.Horner said: "Seven cars in the top 10 have a Mercedes engine. That says it all." Germany's Auto Motor and Sport was quoting sources estimating the power deficit at between 29kW and 52kW.'TOUGH TO FIND A BUYER'With the mandatory engine development 'freeze', there is little Renault can do short of arguing to the International Automobile Federation that the rules should be relaxed so that Mercedes' rivals have a chance.Red Bull racing adviser Helmut Marko said: "That will not happen. The focus is on 2015." But now the latest shock rumour: New York Times correspondent Michael Schmidt said he has heard paddock whispers that the F1 engine facility at Viry-Chattilon in Paris was for sale.Schmidt said F1 was costing Renault "more than expected" at some €50-million (R724-million) per season, with the rest coming from customers - and some of them are apparently paying late.Making the situation worse, Schmidt explained the PR value for Renault was "rather low". "Only criticism and bad press." According to Mercedes' Niki Lauda, however, Renault might struggle to find a buyer, because of restrictive working regulations in France."In France, they work 37 hours a week. In England 43."