Complex sentence: The No.8 Toyota stopped leaving the second Mulsanne Chicane with an oil supply problem that necessitated the team to change its engine but returned to the track with ten minutes remaining although it fell to fourth as Buemi could not improve on the car's best time.
Split into simpler sentences: The No.8 Toyota stopped leaving the second Mulsanne Chicane with an oil supply problem that necessitated the team to change its engine. It returned to the track with ten minutes remaining but the Toyota fell to fourth as Buemi could not improve on the car's best time.