Procedures
Camshafts and hydraulic chain tensioner, removing and installing
^ Cylinder head installed
Special tools, testers and auxiliary items
^ Counter- hold tool 3036
^ Retainer for chain tensioner 3366
^ Puller T40001
Removing
^ Remove ribbed belt and tensioning element for ribbed belt.
^ Remove engine cover panel above cylinder head.
^ Remove toothed belt guard (upper section).
^ Set crankshaft to markings for TDC of No. 1 cylinder - arrows - by turning central bolt on crankshaft sprocket in direction of rotation.
^ Remove cylinder head cover.
^ Screw M5x55 stud - 1 - into toothed belt tensioning element.
^ Screw hexagonal nut - 2 - onto stud - 1 - using large washer- 3 -.
^ Only tension piston of tensioning element as far as necessary to secure it with a locking pin (e. g. from lifting appliance 2024 A) - arrow -.
Notes: If it is not possible to insert the locking pin, carefully tension the pressure piston of the tensioning element just enough to allow the toothed belt to be removed.
^ Take toothed belt off camshaft sprocket.
^ Loosen camshaft sprocket (using 3036).
^ Remove camshaft sprocket using puller T40001.
^ Remove Hall sender housing.
^ Remove rotor for Hall sender.
^ Secure hydraulic chain tensioner with retainer for chain tensioner 3366.
Notes: If the retainer for chain tensioner is tightened excessively, this can damage the hydraulic chain tensioner.
^ Recheck TDC position of camshafts.
^ The marks on the two camshafts must be in line with the arrows on the bearing caps.
^ Clean chain and camshaft sprockets opposite the two arrows on the bearing caps and mark installation position with colored marks.
- The distance between the two arrows (and thus between the colored markings) is 16 rollers on the chain.
- The notch on the exhaust camshaft is offset slightly toward the inside in relation to chain roller- 1 -.
Notes: Do not mark chain with a center punch or by making a notch or similar.
^ First remove bearing caps 3 and 5 on intake and exhaust camshafts.
^ Remove double bearing cap.
^ Remove both bearing caps next to intake and exhaust camshaft chain sprockets.
^ Unscrew securing bolts of hydraulic chain tensioner.
^ Loosen bearing caps 2 and 4 of intake and exhaust camshafts alternately and diagonally, and remove.
^ Remove intake and exhaust camshafts with hydraulic chain tensioner.
Installing
^ Replace rubber/metal gasket for hydraulic chain tensioner and apply a thin coat of sealant "D 454 300 A2" to the shaded area.
^ Fit drive chain on camshaft sprockets as follows:
- When the old chain is being re - installed, fit the chain so that the colored markings are in line - arrows -.
- When a new chain is being installed, the distance between the notches - A - and - B - on the camshafts must be 16 rollers on the chain. The illustration shows the exact positions of the 1st and 16th rollers on the sprockets.
- Notch - A - is offset slightly toward the inside in relation to chain roller - 1 -.
^ Insert hydraulic chain tensioner into the chain.
^ Locate camshafts together with chain and hydraulic chain tensioner on cylinder head.
^ Oil running surfaces of both camshafts.
Notes:
- Dowel sleeves for bearing caps and hydraulic chain tensioner must be located in cylinder head.
- When installing bearing caps ensure that the identification mark is readable from the intake side of cylinder head.
^ Tighten mountings of hydraulic chain tensioner (watch position of dowel sleeves).
^ Tighten bearing caps 2 and 4 of intake and exhaust camshafts in stages and in diagonal sequence (watch position of dowel sleeves).
^ Install the two bearing caps next to the chain sprockets on the intake and exhaust camshafts.
^ Check correct setting of camshafts:
- The two markings on the camshafts must be in line with the two arrows on the bearing caps - arrows -.
- The distance between the two arrows on the bearing caps (or between the colored markings) is 16 rollers on the chain.
- The notch on the exhaust camshaft is offset slightly toward the inside in relation to chain roller - 1 -.
^ Remove holder for chain tensioner 3366.
^ Apply a thin coat of sealant "D 454 300 A2" to shaded area on double bearing cap and install bearing cap (watch position of dowel sleeves).
^ Install remaining bearing caps (watch position of dowel sleeves).
^ Install new intake and exhaust camshaft oil seals.
^ Install camshaft sprocket.
^ Check installation position: the narrow web of the camshaft sprocket faces outward -arrows - and the marking for No. 1 cylinder TDC is visible from the front.
^ Install securing bolt for camshaft sprocket (hold in place with retainer 3036).
^ Install Hall sender.
^ Install cylinder head cover.
^ Align camshaft sprocket mark with marking on cylinder head cover.
^ Align marking on vibration damper with marking on lower part of toothed belt guard.
Notes: The crankshaft not be at TDC when the camshaft is rotated, otherwise valves can contact pistons and cause damage.
^ Install toothed belt (adjust valve timing).
^ Install ribbed belt and ribbed belt tensioning element.
Notes:
^ Follow all instructions for removing and installing toothed belt.
^ Wait about 30 minutes after installing the camshafts before staffing the engine. The hydraulic valve compensating elements must settle (otherwise the valves will strike the pistons).
^ After working on the valve gear, turn the engine carefully at least 2 rotations to ensure that none of the valves make contact when the starter is operated.