To remove the inlet manifold and high-pressure fuel pump, start by taking off the camshaft cover and undoing the retaining bolts to detach the cover from the chain adjuster at the left-hand end of the cylinder head. Lock the tensioner in place using VAG tool T10092 and an MS nut, or alternatively, a 5 mm bolt and locknut, then undo the tensioner retaining Trox bolts. Paint alignment marks between the chain links, the adjuster, and the inlet sprocket, counting the number of links for potential chain renewal. Remove the camshaft sprocket, then gradually slacken and remove the camshaft bearing ladder Trox bolts before lifting the camshafts along with the tensioner and chain from the cylinder head, disengaging the camshafts from the chain and discarding the oil seal. Lift the rocker arms and hydraulic tappets from their bores, storing them with the valve contact surface facing downwards to prevent oil drainage, and keep them immersed in oil while removed, noting their positions for reassembly. Visually inspect each camshaft for wear, looking for smooth surfaces and signs of scoring or excessive wear, and check for discoloration that may indicate overheating. Measure the camshaft end float by temporarily refitting the camshaft and using a DTI gauge, ensuring the hydraulic tappets are not fitted during this measurement. Check that the end float measurement is within limits, considering renewal of the camshaft, cylinder head, and bearing ladder if necessary. For refitting, smear clean engine oil onto the hydraulic tappets and rocker arms before positioning them in the cylinder head, lubricating the camshaft lobe contact surfaces. Refit the chain onto the camshaft sprockets, aligning the previously made marks, and ensure the cylinder head bolt cut-outs in the camshafts face each other. Lubricate the running surfaces of the cylinder head and camshafts, then lay the camshafts in position. Apply a 2.0 mm wide bead of sealant to the grooves on the underside of the bearing ladder and fit it to the cylinder head, tightening the new bolts in stages until contact is made with the mating surface, then to the specified torque. Use VAG special tool T10252 to check alignment, or have an assistant hold the exhaust camshaft stationary while rotating the inlet camshaft to equalize chain free play. Fit new camshaft seal(s), reattach the camshaft sprocket, and apply thread-locking compound to the tensioner retaining bolts after removing the locking bolt. Finally, reattach the camshaft adjuster rear cover with a new gasket, tighten the retaining bolts, and refit the camshaft cover, high-pressure fuel pump, and inlet manifold.