There are two techniques of dismantling the rocker arms and lash adjusters of this engine however the manufacturer prefers the technique that allows removal of the rocker arms and lash adjusters together without having to remove the 
Camshaft(s) and this they can be done by using the special valve spring compressor meant for the engine. This proceeds from the camshaft, and accompanied with a ratchet or a breaker bar, it depresses the valve spring so that tension on the rocker arm is removed. The other method of its measurement entails the withdrawal of the camshaft for measurements to be made on it. First, remove the valve cover(s) and place the valve spring compressor tool in position and compress the spring only to take the rocker arm loose. Before proceeding the camshaft rocker arms and hydraulic lash adjusters have to be refitted in the positions they were removed from, so do not forget to label all the parts before storing them. Subsequently, disconnect the hydraulic lash adjuster and make sure you set aside things that will need to be reassemble. If the vehicle has very high trip settings, the adjusters might be built to last longer and rather stubborn to come out; use of penetrating oil will be helpful. Visual check each adjuster for wear and possible damage, such as pitting or discoloration, and consider to replace it in case doubts concerning it or in case of existence of the noise in the valve train are presupposed. An ordinary hair-pin or a twig of a paperclip can be used to touch the plunger to feel whether it has a restricted movement of not more than 1.5mm. Recommended for adjustment when one of the carriers requires replacement, it is better to replace the entire set and then avoid using more cash for repair. Also be sure also to check the conditions of the rocker arms by applying pressure to them to see signs of wear or damage. Prior to the installation of the lash adjusters, purge them of air as follows: stand the lash adjusters vertically in the oil and with the help of a thin wire or paper clip work the plunger. Coat the tip of stem, the rocker arm, the lash adjuster bore with clean engine oil; place the lash adjusters and the rocker arms with the aid of compressed valve spring. This is a process of removal and hence the steps followed here are the reverse of the steps that were highlighted during installation process. Modified lash adjusters will make some noise when starting until the air is cleared off; to reduce the noise on start up, change the engine speed from idle position to 3,000 rpm for one minute after the engine is warm.