The FIA has sent out new advice to teams intended to stamp out a loop hole by which they might be able to enhance qualifying performance by burning more oil.
Oil burn has been one of the ways of implementing a Saturday 'party mode' that increased single lap speed during qualifying.
"If you were to find a way of using lubricants in a different way in qualifying, it offers a significant performance increase" Red Bull boss Christian Horner pointed out in February.
It's believed that Mercedes scaled back its approach to qualifying modes over the winter in response to new orders from the governing body. But other teams may still be running things closer to the edge and finding ways around the ban.
In particular, teams considering using oil burning could potentially top up their car's oil system in the garage or pit box before it's scrutineered.
That would prevent the FIA officials from detecting a higher than usual rate of oil burn during the session.
It's not thought that any team is currently using this workaround, but the FIA is keen to head off the possibility before it becomes a reality.
Accordingly, the FIA is taking steps to ensure that anyone still using oil burning in qualifying will have to stop. A new directive expressly forbids teams from topping up oil systems during qualifying.
According to Autosport magazine, the FIA's technical delegate Jo Bauer has taken action "following numerous discussions on the subject."
"We wish to clarify that in order to allow the FIA to monitor oil consumption during the qualifying practice session in a precise and timely manner, no oil may be added to the car nor may any auxiliary oil tank (AOT) be activated."
Bauer continued: "There may be no oil transfer between an AOT and any part of the engine lubrication system.
"Exceptions to the above may however be granted on specific occasions following a request from the team concerned.
"Any such exception will be made at the sole discretion of the FIA technical delegate," the directive adds.
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