Jun.26 (GMM) Valencia flagged a major headache for F1 engine supplier Renault.
Not only did Lotus' Romain Grosjean break down with a failed alternator, so too did Red Bull's Sebastian Vettel.
Initially, it appeared the failures were coincidental, but Germany's Auto Motor und Sport now reports a common link.
And, reportedly, Renault now suspects that a problem suffered by Caterham's Vitaly Petrov in Monte Carlo was also similar.
The unit is reportedly manufactured in cooperation between Renault and Magneti Marelli.
"We don't know what has broken, but we believe it's the same source," said engine boss Rob White.
He also doubts the initial diagnosis that the alternators overheated, in light of the possibility that Petrov's Monaco failure was the same.
Lotus team owner Gerard Lopez agrees: "I heard it was the heat, but we have had races that were just as warm, and you would have to wonder why Kimi or Mark Webber weren't affected too."
Renault works very closely with Red Bull, the French marque's premier partner.
"We know now that it's a problem area," said world champion Vettel, "so we need to work to resolve it as soon as possible."