Timing Component Alignment Marks: Locations
Camshaft Timing Chain
Special tools, testers and auxiliary items required
• Camshaft Bar (T10068 A)
• Black Sealant
• Sealing Compound
Removing the camshaft timing chain
• Engine installed.
- Drain the coolant. Refer to => [ Cooling System, Draining and Filling ] Procedures.
- Remove the intake manifold.
- Disconnect electrical connector to engine coolant temperature (ECT) sensor (G62).
- Disconnect coolant hoses at positions indicated by - arrows -.
- Remove the bolts - arrows -.
- Pull transmission oil cooler coolant pipe bracket toward left.
- Swing Secondary Air Injection (AIR) system hose bracket forward.
- Remove bolt - arrow - at wiring harness bracket.
Press coolant pipe in direction of coolant pump using pry bar when removing coolant thermostat housing so that is not pulled off.
- Remove coolant thermostat housing - 2 - while pressing coolant pipe - 1 - toward coolant pump with pry bar.
Vehicles with engine code BUB:
- Disconnect the hose - 3 - and the vacuum hose - 2 - from the Secondary Air Injection (AIR) combination valve.
- Disconnect coolant hose - 1 -.
Vehicles with engine code CBRA:
- Disconnect the hose - 1 - and the vacuum hose - 2 - from the left Secondary Air Injection (AIR) combination valve.
• Ignore - 3 - and - arrows -.
All Vehicles
- Identify and disconnect electrical connectors:
1. Camshaft position sensor (G40)
2. Camshaft position (CMP) sensor 2 (G163)
3. Camshaft adjustment valve 1 (N205)
4. Camshaft adjustment valve 1 (exhaust) (N318)
- Remove wiring guide from camshaft timing chain cover.
- Loosen cylinder head cover bolts in sequence - 11 to 1 -.
- Set crankshaft to TDC mark by turning crankshaft on vibration damper screw in direction of engine rotation - arrow -.
- Cams - A - of cylinder 1 must face each other.
- At the same time, (T10068 A) must engage in both shaft grooves. Turn crankshaft 1 additional turn if necessary.
- Remove camshaft timing chain tensioner - arrow -.
- Remove bolts - 1 to 3 - and upper timing chain cover horizontally from cylinder head. When doing so, ensure cylinder head bolt is not damaged.
- Remove bolts - arrows - and remove guide track - 1 -.
- Remove (T10068 A).
• Camshaft bar (T10068 A) must not be inserted when loosening or tightening camshaft adjuster screws.
- Remove retaining screw at intake side camshaft adjuster while counterholding camshaft hex head with open end wrench SW 32.
- Remove intake side camshaft adjuster.
- Remove retaining bolt at exhaust side camshaft adjuster while counterholding camshaft hex head with open end wrench SW 32.
- Remove camshaft adjuster exhaust side.
- Lay camshaft timing chain over camshaft adjuster valves.
Installing the camshaft timing chain (adjusting the timing)
• Tightening specifications, refer to => [ Timing Chain Covers Assembly Overview ] Service and Repair, => [ Upper Timing Chain Cover - Tightening Specifications and Tightening Sequence ] Service and Repair and => [ Timing Chain Component Overview ] Timing Chain Component Overview.
- Insert guide track - 1 - and tighten bolts - arrows -.
- Check TDC marking on crankshaft again - arrow -.
- Verify camshaft TDC position:
• Cams - A - of cylinder 1 must face each other.
• It must be possible to insert (T10068 A) into both shaft grooves.
- If necessary, turn camshafts at hex head surfaces - arrows - to correct position using open end wrench SW 32.
Risk of damaging valves and piston crowns.
• If camshafts are rotated, crankshaft may not rest with any piston at "TDC".
• Both camshaft adjusters (identification: 24E on intake side and 32A on exhaust side) can only be bolted in one position on the camshaft mountings - arrows - by an alignment pin.
- First install intake side camshaft adjuster:
- Turn sensor wheel - 1 - in camshaft adjuster clockwise - arrow - to stop.
• Camshaft bar (T10068 A) must not be used as counterhold.
- Hand tighten intake side camshaft adjuster in this position to intake camshaft.
• Contact surface of sensor wheel at screw head must be dry when installing.
• The "24E" marking - 1 - and the tooth behind it must align with notch - 2 - in control housing. Markings on control housing => [ Markings on Control Housing with MPI Engines ] Timing Chain Component Overview.
- Lay camshaft timing chain in this position tightly against intake side camshaft adjuster sprocket.
- Starting with the toothed that has the "24E" marking, count exactly 16 rollers to the right on the timing chain. Mark this roller with a color marker.
• Exhaust camshaft adjuster is locked in the rest state. Therefore sensor wheel cannot be rotated when adjusting the valve timing. If locking mechanism is in rest state is not engaged (locked) turn adjuster in both directions by hand until it locks. If that is not possible, replaced camshaft adjuster.
- Now insert exhaust camshaft adjuster "32A" with tooth at arrow marking - 1 - into camshaft roller chain so that the exact, previously counted 16 rollers lie between marking "24E" and "32A" and markings - 1 - and - 2 - align.
- Exhaust camshaft adjuster must be able to be inserted easily on exhaust camshaft and be tightened hand-tight.
- Check the position of both camshaft adjusters one more time for correct adjustment.
- Remove (T10068 A).
- Tighten bolt on camshaft adjuster intake side by counter-holding with open-end spanner on camshaft hex head.
- Tighten bolt on camshaft adjuster exhaust side by counter-holding with open-end spanner on camshaft hex head.
Risk of timing chain jumping off.
• If the crankshaft is rotated, forcefully press camshaft tensioning rail by hand (instead of with chain tensioner) against camshaft adjuster timing chain - arrow -.
- Set crankshaft to TDC mark by turning crankshaft on vibration damper bolt 2 turns in direction of engine rotation - arrow -.
- Cams - A - of cylinder 1 must face each other.
At the same time, the (T10068 A) must engage in both shaft grooves.
If the camshaft bar cannot be inserted:
- Repeat valve timing adjustment.
- Clean old sealant from 3 mm holes - arrows - in cylinder head seal.
- Fill 3 mm holes in cylinder head seal using black sealant.
• With the cylinder head installed only half of the holes in the cylinder head gasket are visible.
- Replace seal in upper timing chain cover. Refer to => [ Upper Timing Chain Cover Seal, Replacing ] Upper Timing Chain Cover Seal, Replacing.
- Clean sealing surfaces so they are completely free of any oil or grease.
- Check whether fitting sleeves - 2 - and - 3 - are inserted in upper timing chain cover.
- Insert a new gasket - 1 - and a new seal - 4 -.
- Lightly coat clean upper timing chain cover sealing surfaces - shown hatched - with sealing paste.
• Also coat sealing surfaces below cylinder head seal with some sealant do not kink cylinder head seal when doing so.
• Upper timing chain cover must be installed within 5 minutes of applying sealing paste.
- Set upper timing chain cover in place and tighten bolts as follows:
1. Tighten bolts - 1 - and - 2 - to 5 Nm.
2. Tighten the bolts - 3 - to 23 Nm.
3. Tight the bolts - 1 - and - 2 - to 10 Nm.
- Tighten camshaft timing chain tensioner - arrow -.
- Turn crankshaft 2 times in direction of engine rotation and check valve timing again.
- Install cylinder head cover. Refer to => [ Cylinder Head Cover ] Service and Repair.
- Install intake manifold.
- Install coolant thermostat housing. Refer to => [ Coolant Thermostat Housing ] Service and Repair.
* Replace bolt.
* 90° corresponds to a 1/4 turn