Disconnect the negative terminal from the battery.

Drain the engine coolant.

Remove the breather hose between the air intake hose and the head cover.

Remove the air cleaner.

Remove the timing belt cover.

Remove the head cover and disconnect camshaft position sensor.

Loosen the camshaft sprocket bolts then remove the camshaft sprockets.

Loosen the camshaft bearing cap bolts and remove the bearing caps, camshafts, rocker arms and lash adjusters.

Fuel system is subject to extremely high pressure (1350 bar).

Never perform any work on injection system with engine running or within 30 seconds after stopping the engine.

Always pay attention to safety precautions.

Ensure the absolute cleanliness.

Never remove the injectors.

Check rotation of the roller. If they do not rotate smoothly or are loose, replace them.

Check the roller surface. Replace if there is any dent, damage or evidence of seizure.

Check the valve cap contact surface for possible damage or evidence of seizure. Replace if necessary.

Check the camshaft journals for wear. If the journals are badly worn, replace the camshaft.

Check the cam lobes for damage. If the lobe is damaged or worn excessively, replace the camshaft.

Install the camshafts on the cylinder head.

Install the bearing caps.

Check that the camshaft can be easily turned by hand. After checking, remove the bearing caps and the camshafts, and then install the rocker arms.

Make sure that the dowel pins on the camshaft sprocket ends are located on the top.

Tighten the bearing caps to the specified torque in two or three increments as shown.

Using the special tools, camshaft oil seal Installer. Be sure to apply engine oil to the external surface of the oil seal.

Insert the oil seal along the camshaft front end and install it by driving the installer with a hammer until the oil seal is fully seated.

Install the camshaft sprocket bolts to the specified torque.

Install the rocker cover.