Lincoln 2015 MKZ HYBRID Owner's Manual page 175

Why does my engine rev up so high sometimes when I accelerate?
What is the fan noise I hear from the rear of my hybrid?
How far can I go in Electric Drive if I run out of gas?
What is the engine oil change service interval?
Can I put E15 or E85 in my vehicle, and how will it affect my fuel
MKZ Hybrid (), enUSA
Unique Driving Characteristics
Question
economy?
Your vehicle's engine and transmission are designed to deliver the
power you need at the most efficient engine speed. This may be
higher than expected during heavy accelerations, and may fluctuate
during steady state driving. These are characteristics of the Atkinson
engine cycle and the transmission technology that help maximize
your hybrid's fuel economy.
The fan noise comes from a fan located outside the high voltage
battery. This fan turns on when the battery requires cooling air. The
fan speed and associated noise level will change, according to the
amount of cooling required to maintain good performance. Maintaining
the battery temperature at optimal conditions also prolongs the useful
life of the battery and helps to achieve better fuel economy. Do not
place objects on the package tray which could block air flow through
the hybrid vehicle battery cooling vents.
Running out of gas is not recommended. However, you may be able
to go about one mile, driving at 30 mph (48 km/h), if the battery has
a normal state of charge.
Change the engine oil every 10000 miles (16000 km) under normal
operating conditions. See Scheduled Maintenance (page 476).
Your hybrid vehicle can use E15 (15% ethanol, 85% gasoline) fuel, but
you may notice slightly reduced fuel economy because ethanol
contains less energy per gallon than gasoline. Your hybrid vehicle is
not designed to use E85 (85% ethanol).
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