The 2015 and 2016 Hyundai Sonata and Kia Optima share near-identical 2.4-liter inline 4-cylinder, 2.0-liter turbocharged 4-cylinder, and 1.6-liter turbocharged 4-cylinder engines, and all three need the same sort of air filter service approximately every 50,000 miles (depending on driving conditions).
If performed by you or your mechanic, it is a straightforward operation that ensures free-flowing fresh air for your Hyundai or Kia's induction system. It is especially important for turbocharged engines since they use even more air, and a step-up replacement air filter like the K&N 33-5026 will enhance acceleration and are designed to boost horsepower and acceleration.
K&N's 33-5026 engine air filter fills this bill and is a direct replacement for the stock filter in both the Sonata and Optima. It is a drop-in design manufactured from a special oiled cotton gauze and mounted in a polyethlene frame. It comes with an additional plastic frame to create an even better fit in the air box. Installation requires no tools and can be accomplished in about 5 minutes.
When it is time to check or clean the filter, simply reverse the installation steps, and clean and refresh the cotton gauze using K&N's 99-5000 filter care service kit.