GM 12681018 Camshaft Phaser Bolt for 2014-2018 Gen V L83 L86 5.3 6.2 EnginesChevrolet Performance engine variable valve timing solenoids regulate oil flow to the cam phasers that change the timing of the camshafts. The desired positions of the camshaft varies with engine speed and load and is calibrated for optimal engine performance, drive quality, and efficiency. These solenoids are GM recommended replacements for your vehicle's original components. These original equipment solenoids have been manufactured to fit your GM