The FIA has continued to pursue the controversial issue of oil burning by telling teams it will impose a new limit on consumption from the Italian Grand Prix.
There has been season-long intrigue about oil burning, with teams reminded that using oil as fuel was illegal before the campaign.
Further limits were then imposed from the Azerbaijan Grand Prix in relation to the use of combustion chemicals in oil.
Although new rules to outlaw oil burn have already been agreed for 2018, the FIA has continued its push to ensure teams are not getting around the limits this season too.
In a Technical Directive issued to the teams ahead of the Hungarian Grand Prix, it has reminded them that an oil consumption limit of 0.6 litres per 100km was deemed to be acceptable – and would now be "strictly enforced" from 2018.
However, mindful that some manufacturers could struggle to get within that limit with current engines, there has been no push to strictly limit oil use up until now.
For having analysed the engine situation over the first half of the year, the FIA has now ruled that any new power unit introduced from the Italian GP will have to adhere to a limit of 0.9 litres of oil use per 100km.
"We have accepted that some competitors may have difficulties in adhering to the 0.6L/100km limit this season and a tolerance is being applied to all power units currently in use," wrote FIA technical delegate Marcin Budkowski.
"However, we will expect the oil consumption of any ICE element of the power unit introduced from the 2017 Italian GP onwards to be less than 0.9L/100km, any consumption above this will be considered suspicious and hence investigated as a potential breach of the Technical Regulations."
The FIA also made it clear that it will be keeping a close eye on the situation, so could not rule out further limits being imposed.
"We will continue to monitor the oil consumption of all competitors and carry out physical inspections and/or measurements on a regular basis," the note added.
F1 teams still have the opportunity to introduce a new V6 to their pools of usable elements in either Hungary or Belgium without having to adhere to the new limits.
However, with the run from Monza to the end of the season comprising nine races, manufacturers are likely to have already scheduled the introduction of performance upgrades later in the year, and will now be forced to ensure that they comply with the new restrictions.