Rumors of Porsche adding a diesel powertrain to the Cayenne have been making the rounds for months, but with almost nothing in the way of official confirmation, and more than one official denial, the existence of an oil-burning Porsche will remain just speculation. Most reports have suggested that Porsche was planning to use an Audi sourced V6 turbodiesel in its Cayenne next year, but according to a spokesman at this week’s Paris Motor Show Audi is yet to give authorization for use of its engines.

Speaking with AutoTelegraaf, the spokesman said Porsche has made no announcement on a Cayenne diesel but was open to borrowing a diesel engine from another carmaker. One major hurdle for Porsche is the infighting that is going on between Porsche and Audi’s parent company Volkswagen Group.

Bad blood between VW chairman Ferdinand Piëch and Porsche CEO and VW board member Wendelin Wiedeking may see any plans for Porsche to borrow Audi technology blocked by Piëch. However, both execs have denied claims of company infighting as just media speculation.

Audi is currently developing a new 3.2L V6 diesel engine with more than 300hp (225kW) and fuel economy of about 30mpg (7.8L/100km) in its sedan models (an SUV would have slightly worse fuel economy figures). Porsche was rumored to be considering the engine for its Cayenne SUV next year and was reported to be planning to build up to 15,000 diesel units per year.

In the Cayenne the new diesel is expected to achieve a fuel economy rating of 23mpg (9.9L/100km), a significant improvement over the current V6 petrol model, which is rated at 18.2mpg (12.9L/100km).