It is important to note that such a procedure can cause a trouble code to be entered and one has to visit a dealer service department or a repair shop with the required scan tool to adjust the cam sensor(s) and remove the trouble code. The camshafts and lifters must always be inspected completely before being installed and the end play of the camshafts must be measured before being removed. Hydraulic lifters are self-adjusting and do not need a periodical service, but excessively noisy hydraulic lifters do have a procedure in their checking. Open the engine cover, and valve cover, as well as any oil deflector(s) to access the camshaft(s). Take out the timing belt and sprockers of the camshaft but make sure that the engine is not on TDC. In the case of SOHC engines, dismount the camshaft position sensor and camshaft plug and label the area where the bearing caps of the cams are with 1, 2, 3, and 4 and remove the two bearing caps in the center and then remove the rest in a turn-taking manner. In cases of DOHC engines, the camshaft position sensor and reluctor ring are removed and the location of the camshaft drive chain is denoted relative to the sprockets. Install the camshaft drive chain tensioner with special tool or improvised tool, and must mark where the camshaft bearing caps are. As one assembly remove the camshafts and drive chain tensioner with the caps in order. Lift the lifters off the cylinder head making sure that they are arranged according to their corresponding valves. Checks on camshafts, lifters When clean engine oil is applied on the sides of the hydraulic lifters, they should be installed in position. Apply oil to the camshaft and bore journals on the cylinder head, check the camshaft by positioning it into the cylinder head carefully and apply bearing caps with RTV sealant and tightening the retaining nuts to appropriate torque. In the case of DOHC engines, wipe the mating surfaces on the drive chain tensioner, fit the end plugs and gasket and align the marks on the drive chain with the notches on the camshaft drive gears. Lube journal of the camshaft and cylinder head bearings, load the camshafts, drive chain, and tensioner and fit the drive chain tensioner. Install camshaft bear caps in the opposite order of removal with the RTV sealant on the mating surfaces. Wipe out the oil seals housings, lubricate the lips of new camshaft oil seals and force them in. Fit the camshaft sprockers and connect the bolts with your fingers, then fit in the timing belt, and make sure these are correctly in place. The rest of the installation is done in reverse sequence of the removal with a warning not to start the vehicle immediately but wait at least 30 minutes to enable the new lifters to bleed down to avoid the severe damage to the engine.