Variable Valve Timing Actuator: Service and Repair
Camshaft Adjusters
Special tools, testers and auxiliary items required
• Spanner Wrench (3212)
• Multipoint Socket (T10035)
• Retainer (3036)
• Socket (T40058)
• Locking Pin (T40069)
• Locking Pin (T40071) (Qty: 2)
• Camshaft Clamp (T40133)
Removing
Risk of injury from coolant fan starting by itself.
• The coolant fan can come on even when the ignition is turned off, for example, caused by the heat still in the engine compartment.
• The camshaft timing chains remain on the engine in the following procedure.
- Remove the left and right upper timing chain covers. Refer to => [ Left or Right Upper Timing Chain Cover ] Left or Right Upper Timing Chain Cover.
- Remove the cylinder head covers, refer to the following:
• => [ Left Cylinder Head Cover ] Left Cylinder Head Cover.
• => [ Right Cylinder Head Cover ] Right Cylinder Head Cover.
- assemble the socket (T40058) as follows:
• The large diameter end - arrow 1 - faces the engine.
• The small diameter end - arrow 2 - is inserted in the socket.
- Rotate the crankshaft in engine rotation direction - arrow - to Top Dead Center (TDC) using the socket (T40058) and a box end wrench.
• The notch - A - has to match up with the joint - arrow -.
• The threaded holes - arrows - in the camshafts must face upward.
- Remove the plug - arrow - from the cylinder block.
- Install the locking pin (T40069) in the hole and tighten it to 20 Nm. Rotate the crankshaft - 1 - back and forward slightly to completely center the pin, if necessary.
- Secure the cylinder bank 1 camshaft in place at TDC using the camshaft clamp (T40133/1) and tighten the bolts - arrows - to 25 Nm.
- Secure cylinder bank 2 camshaft in place at TDC using the camshaft clamp (T40133/2) and tighten the bolts - arrows - to 25 Nm.
- Press the left camshaft timing chain tensioner guide rail in as far as the stop using a screwdriver - 1 - and secure the chain tensioner using a locking pin (T40071).
• The chain tensioners for the camshaft timing chains are oil-dampened. They can be pressed together only with slow and even pressure.
- Press the right camshaft timing chain tensioner guide rail in as far as the stop using a screwdriver - 1 - and secure the chain tensioner using a locking pin (T40071).
The camshafts can get damaged.
• Do not use the camshaft clamps (T40133) to counter hold when loosening the camshaft adjuster bolt or the camshaft sprocket bolt.
- To counter hold the camshaft adjuster, install the retainer (3036) to the camshaft adjuster and loosen the bolt using the multipoint socket (T10035).
- To counter hold the camshaft sprocket, install the spanner wrench (3212) on the camshaft sprocket and loosen the bolt using the multipoint socket (T10035).
• Ignore - item 1 - and the - arrow -.
The engine could be destroyed.
• To prevent small parts from accidentally entering the engine through the opening in the timing chain compartment, cover the opening with a clean cloth.
- Remove the bolts - 1 and 2 - from the left cylinder head, then remove the camshaft adjuster and the camshaft sprocket.
- Remove the bolts - 1 and 2 - from the right cylinder head, then remove the camshaft adjuster and the camshaft sprocket.
Installing
- Refer to one of the following:
• => [ Installing, Cylinder Bank 1 (Right Side) ]
• => [ Installing, Cylinder Bank 2 (Left Side) ]
Installing, Cylinder Bank 1 (Right Side)
• For the correct tightening specifications, refer to => [ Camshaft Timing Chain Overview ] Camshaft Timing Chain Overview.
• Replace the bolts which have been tightened to an additional torque angle.
Risk of damaging valves and piston crowns.
• If the camshafts are rotated, the crankshaft may not rest with any piston at Top Dead Center (TDC).
• Secure the crankshaft - 1 - in the TDC position using the locking pin (T40069).
• The camshafts are secured in place at TDC using the camshaft clamp (T40133/1) and the bolts - arrows - are tightened to 25 Nm.
- Position the timing chain on the camshaft adjuster - A - and place the camshaft adjuster on the camshaft. Watch for the following:
• The timing chain must be positioned "tightly" against the guide rail - left arrow -.
• Manually hold the timing chain under tension in the - direction of the arrow -.
• The groove - 1 - in the camshaft adjuster must align with the adjustment window - 2 -.
- Install the camshaft sprocket in the timing chain and place the camshaft sprocket on the camshaft. Watch for the following:
• The mark - 1 - must be centered with the adjustment window - 2 -.
- Loosely install the bolts - 1 and 2 -. The camshaft adjuster and the camshaft sprocket must be able to still be rotated on the camshafts and must not tilt.
- Use a screwdriver to press the right camshaft timing chain tensioner guide rail in as far as the stop - 1 - and remove the locking pin (T40071).
- Install the spanner wrench (3212) to the camshaft sprocket.
- Press the spanner wrench (3212) in the - direction of the arrow -, check whether the timing chain is lying "tightly" against the guide rail - A -. If the timing chain still has "slack", then shift the camshaft sprocket by one gear tooth.
- Maintain the preload tension on the camshaft timing chain with the help of a second technician by using the spanner wrench (3212) and turn rotate in the - direction of the arrow -.
- Tighten the bolts as follows while the camshaft sprocket is still held under tension.
1 - Tighten the exhaust camshaft bolt to 80 Nm
2 - Tighten the intake camshaft bolt to 80 Nm
- Tighten the bolts to the final tightening specification. Do this by counter holding the retainer (3036) or the spanner wrench (3212).
1 - Continue tightening the exhaust camshaft bolt an additional 90° (1/4) turn. Continue counter holding using the spanner wrench (3212).
2 - Continue tightening the intake camshaft bolt an additional 90° (1/4) turn. Continue counter holding using the retainer (3036).
Installing, Cylinder Bank 2 (Left Side)
• For the correct tightening specifications, refer to => [ Camshaft Timing Chain Overview ] Camshaft Timing Chain Overview.
• Replace the bolts which have been tightened to an additional torque angle.
Risk of damaging valves and piston crowns.
• If the camshafts are rotated, the crankshaft may not rest with any piston at Top Dead Center (TDC).
• Secure the crankshaft - 1 - in the TDC position using the locking pin (T40069).
• The camshafts are secured in place at TDC using the camshaft clamp (T40133/2) and the bolts - arrows - are tightened to 25 Nm.
- Position the timing chain on the camshaft adjuster - A - and place the camshaft adjuster on the camshaft. Watch for the following:
• The timing chain must be positioned "tightly" against the guide rail - arrow -.
• Manually hold the timing chain under tension in the - direction of the arrow -.
• The groove - 1 - in the camshaft adjuster must align with the adjustment window - 2 -.
- Install the camshaft sprocket in the timing chain and place the camshaft sprocket on the camshaft. Watch for the following:
• The mark - 1 - must be centered with the adjustment window - 2 -.
- Loosely install the bolts - 1 and 2 -. The camshaft adjuster and the camshaft sprocket must be able to still be rotated on the camshafts and must not tilt.
- Use a screwdriver to press the right camshaft timing chain tensioner guide rail in as far as the stop - 1 - and remove the locking pin (T40071).
- Install the retainer (3036) to the camshaft adjuster.
- Press the retainer (3036) in the - direction of the arrow - and check whether the timing chain fits "tautly" against the guide rail - A -. If the timing chain still has "slack", then rotate the camshaft sprocket by one gear tooth.
- Maintain the preload tension on the camshaft timing chain with the help of a second technician by using the retainer (3036) and rotate in the - direction of the arrow -.
- Tighten the bolts as follows while the camshaft adjuster is still held under tension.
1 - Tighten the intake camshaft bolt to 80 Nm
2 - Tighten the exhaust camshaft bolt to 80 Nm
- Tighten the bolts to the final tightening specification. Do this by counter holding the retainer (3036) or spanner wrench (3212).
1 - Continue tightening the intake camshaft bolt an additional 90° (1/4) turn. Continue counter holding using the retainer (3036).
2 - Continue tightening the exhaust camshaft bolt an additional 90° (1/4) turn. Continue counter holding using the spanner wrench (3212).