Cylinder Heads
Cylinder Heads
Special tools, testers and auxiliary items required
• Spanner Wrench (3212)
• Locking Pin (T40069)
• Camshaft Clamps (T40133)
Removing
• Engine installed.
• The following information describes how to remove both cylinder heads at the same time.
• If only one cylinder head will be removed, follow the applicable instructions in the following description.
There is a risk of injury because the fuel is under very high pressure.
• Reduce the fuel pressure down to residual pressure before opening high pressure area of the fuel injection system.
- Reduce fuel pressure in the high pressure area.
- Remove the front exhaust pipe. Refer to => [ Left Front Exhaust Pipe with Catalytic Converter ] Left Front Exhaust Pipe with Catalytic Converter, => [ Right Exhaust Pipe with Catalytic Converter ] Right Exhaust Pipe with Catalytic Converter.
- Remove the front left coolant pipes. Refer to => [ Left Front Coolant Pipes ] Left Front Coolant Pipes.
- Remove ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Remove the upper coolant pipe. Refer to => [ Upper Coolant Pipe ] Upper Coolant Pipe.
- Remove the lower section of the intake manifold.
- Disconnect the electrical connectors on the fuel injectors.
- Remove the threaded connection - 2 - and move the fuel supply line to the side.
- Disconnect electrical connectors - 1 - and - 6 -.
• Ignore items - 3, 4 and 5 - and - arrows -.
- Disconnect the electrical connectors on the left cylinder head:
1 Camshaft position (CMP) sensor 2 (G163)
3 Camshaft adjustment valve 2 (N208)
• Ignore item - 2 - and - arrows -.
- Move the electrical wiring harness to the side.
- Disconnect the electrical connectors on the right cylinder head:
1. Camshaft adjustment valve 1 (N205)
2. Camshaft position (CMP) sensor (G40)
• Ignore - arrows -.
- Move the electrical wiring harness to the side.
- Remove the affected camshaft timing chain from camshafts. Refer to => [ Camshaft Timing Chains, Removing from Camshafts ] Camshaft Timing Chains, Removing from Camshafts.
- Remove the left front coolant hose in the engine compartment; to do this, lift the clips - arrows -.
- Remove the coolant hose - arrow - from the front coolant pipe by lifting the retaining clamp.
- Remove the bolt - arrow - and remove the oil dipstick with the guide tube.
- Remove the vacuum hose from the vacuum pump - 1 - and free it up.
• Ignore - arrows -.
- Disconnect the vacuum hose - arrow - leading to the leak detection pump (V144).
- Remove the bolts for the coolant pump ribbed belt pulley, using a (3212) to counterhold.
- Remove the ribbed belt pulley.
- Disconnect electrical connector - 2 - for Engine coolant temperature (ECT) sensor (G62).
- Remove the front coolant pipe bolts - arrows -.
• Ignore - 1 -.
- Remove the bolts for the power steering pump ribbed belt pulley, using a (3212) to counterhold.
- Remove the ribbed belt pulley.
- Remove the bolts - 1 - and - 2 - and lay the power steering pump to the side.
- Disconnect the electrical connector - 1 - for the heated oxygen sensor (HO2S) (G39) and free up the wire.
• Ignore - 2 -.
- Disconnect the electrical connector - 1 - for the heated oxygen sensor (HO2S) 2 (G108) and free up the wire.
• Ignore - 2 -.
- Remove the bolts - arrows - on the rear of the cylinder head.
• Left cylinder head: 3 bolts.
• Right cylinder head: 4 bolts.
- Loosen the cylinder head bolts in the following sequence - 1 through 8 -.
- Remove the bolts, remove the cylinder head and place it on a soft surface (foam).
Installing
• Tightening specifications, refer to => [ Cylinder Head Overview ] Cylinder Head Overview.
The sealing surfaces could be damaged.
• Carefully remove sealant residue from cylinder head and cylinder block.
• Make sure that no long scrapes or scratches result.
Risk of damaging cylinder block.
• There must be no oil or coolant in the blind holes for the cylinder head bolts in the cylinder block.
Risk of cylinder head seal leaking.
• Carefully remove sealant residue from cylinder head and cylinder block. Make sure that no long scrapes or scratches result.
• Carefully remove all grinding and sanding residue.
• Only unpack new cylinder head gasket immediately prior to installation.
• To prevent cylinder head seal silicone layer and recessed area from being damaged, always handle seal extremely carefully.
Risk of damaging open valves.
• If a replacement cylinder is installed, only remove plastic base right before cylinder head is installed to protect open valves.
Risk of damaging valves and piston heads after working on valvetrain.
• To ensure valves do not strike pistons when starting, carefully rotate engine at least 2 full revolutions.
• Replace bolts which have been tightened to an additional torque.
• Replace self-locking nuts, sealing rings, seals and O-rings.
• Note different sealant for cylinder head sealing surfaces and bolts.
• When installing a replacement cylinder head with the camshaft installed, coat the contact surfaces between the hydraulic adjusting elements, the roller rocker levers and cam running surfaces with oil.
• The hose connections as well as the air guide pipes and hoses must be free of oil and grease before installing.
• Secure all hose connections with hose clamps appropriate for the model.
• In order to be able to securely mount the air guide hoses on their connectors, spray the screws on the previously used clamps with a rust remover.
• The engine oil and coolant must be changed if the cylinder head or cylinder head seal are replaced.
• Secure the camshafts in the "TDC" position on both cylinder heads using the (T40133) - arrows - (25 Nm).
• The (T40133) is correctly positioned when the holes for the cylinder head bolts remain free.
• Secure crankshaft - 1 - in "TDC" position using crankshaft holder (T40069).
- Install new seals and O-rings for the front coolant pipe.
- Set cylinder head gasket in place.
• Installation position: The marking "top" or the part number must be legible.
• Pay close attention to alignment bushings in cylinder block - arrows -.
- Set cylinder head in place.
- Tighten the cylinder head bolts. Refer to => [ Cylinder Head, Tightening Specifications
and Sequence ] Cylinder Head Overview.
- Tighten the bolts - arrows -.
• Left cylinder head: 3 bolts.
• Right cylinder head: 4 bolts.
• Do not tighten the cylinder head bolts.
The rest of the installation is performed in reverse order of removal, noting the following:
- Install the camshaft timing chains. Refer to => [ Camshaft Timing Chains, Removing from Camshafts ] Camshaft Timing Chains, Removing from Camshafts.
- Install the lower section of the intake manifold.
- Install front coolant pipe. Refer to => [ Front Coolant Pipe ] Front Coolant Pipe.
- Install the upper coolant pipe. Refer to => [ Upper Coolant Pipe ] Upper Coolant Pipe.
- Install oil dipstick guide tube. Refer to => [ Oil Dipstick Guide Tube - Tightening
Specifications ] Cylinder Head Overview.
- Install the ribbed belt. Refer to => [ Ribbed Belt ] Ribbed Belt.
- Install the left front coolant pipes. Refer to => [ Left Front Coolant Pipes ] Left Front Coolant Pipes.
- Install the front exhaust pipes with catalytic converter. Refer to => [ Left Front Exhaust Pipe with Catalytic Converter ] Left Front Exhaust Pipe with Catalytic Converter; => [ Right Exhaust Pipe with Catalytic Converter ] Right Exhaust Pipe with Catalytic Converter.
- Change engine oil.
- Replace coolant => [ Cooling System, Draining and Filling ] Procedures.