See also:

Climate control air filter
Filter inspection The climate control air filter should be replaced according to the maintenance schedule. If the vehicle is operated in severely air-polluted cities or on dusty rough roads for a ...

Engine cooling system
The high-pressure cooling system has a reservoir filled with year-round antifreeze coolant. The reservoir is filled at the factory. Check the antifreeze protection and coolant level at least once ...

SOLID RIDE WITH POWER TO SPARE AND EXCELLENT FUEL ECONOMY
In terms of driving characteristics, the Optima is very much in keeping with the Hyundai Sonata, which shares the same platform. The cabin is quiet and the drive is smooth, with the Optima feeling ...