Note that 2015 and later models do not require valve adjustment. Position the number 1 piston at TDC on the compression stroke. Remove the engine cover by pulling it up and off the ball studs. Disconnect the negative battery cable from the remote ground terminal. Blow out the recessed area around the spark plug openings with compressed air, if available, to remove any debris that might fall into the cylinders, then remove the spark plugs. Remove the valve cover. The lobes must be measured one set at a time; rotate the
Camshaft(s) until two lobes on any one cylinder are pointing straight up and measure the clearances of those valves with feeler gauges, ensuring a slight drag on the gauge indicates correct clearance. Rotate the camshaft(s) until all the lobes have been checked. Remove the camshaft(s) for the valve(s) that you intend to adjust. Remove and measure each lifter with a micrometer, recording the measurement for each lifter before moving on to the next. To calculate the correct thickness of a replacement lifter that will put the valve clearance within the specified range, use the formula S - C equals change, where S is the specified valve clearance and C is the measured valve clearance. Remove the lifter and read the size from the bottom, then reduce the lifter by subtracting the specified valve clearance from the measured valve clearance or as close as possible to the calculated size. Install the camshaft(s) and check the valve clearances again to verify they are now within the range. The remainder of installation is the reverse of removal.