Cylinder Head Assembly: Service and Repair
Cylinder head, removing and installing
Notes:
^ Always replace cylinder head bolts when assembling.
^ Replace self - locking nuts.
^ Always replace bolts that are tightened to a specified angle.
^ Always replace sealing rings and gaskets when assembling.
^ When installing an exchange cylinder head with the camshafts the contact surfaces between valve lifter and cam running surface must be oiled after installation of the cylinder head.
^ The plastic protectors fitted to protect the open valves must only be removed immediately before fitting the cylinder head.
^ When fitting a new cylinder head or cylinder head gasket, drain of oil the old coolant and re - fill with new coolant.
^ Cylinder heads, which have cracks between the valve seats or between valve seat inserts and the spark plug thread can be used further without reducing service life, provided the cracks do not exceed a maximum of 0.3 mm in width, or when no more than the first 4 turns of the spark plug threads are cracked.
Refer to Timing Belt, Service and Repair.
Refer to Compression check, Testing and Inspection.
1 - Cylinder head
^ If replaced, replace the coolant completely.
- Refer to Removing cylinder head.
- Refer to Installing cylinder head.
- Checking for distortion, Refer to Fig. 1
- Reworking limit, Refer to Fig. 2
2 - Oil deflector
^ Note installation position: above intake camshaft between No. 1 and No. 2 cylinders
3 - Cylinder head bolt
^ Replace
^ Note sequence when loosening.
^ Note sequence when tightening.
4 - Cylinder head cover gasket
^ Replace if damaged or leaking
^ Before fitting gasket, apply sealant D 454 300 02 to sides of sealing surfaces:
^ Between double bearing cap and cylinder head, Refer to Fig. 3
^ Between hydraulic chain tensioner and cylinder head, Refer to Fig. 4
5 - Cylinder head cover
6 - Gasket
^ For ignition coil
^ Replace if damaged
7 - Ignition coil
^ Testing
8 - 10 Nm
9 - Filler cap
10 - Seal
^ Replace if damaged
11 - 10 Nm
12 - Intake manifold gasket
^ Replace
13 - Cylinder head gasket
^ Refer to Removing cylinder head.
^ Position: Part No. toward cylinder head
^ If replaced, replace the coolant completely.
Fig. 1 Checking cylinder head for distortion
^ Use knife - edge straightedge and feeler gauge to measure at several points.
^ Maximum permissible distortion: 0.1 mm
Fig. 2 Cylinder head reworking limit
Reworking the cylinder head (shaving) is only permitted down to minimum dimension - a -.
Minimum dimension - a - = 139.25 mm
Fig. 3 Sealing transition points between double bearing cap and cylinder head
^ Carefully apply a thin coat of sealant "D 454 300 02" to both edges of sealing surfaces between double bearing cap and cylinder head - arrows - using a small screwdriver.
Fig. 4 Sealing points: hydraulic chain tensioner/ cylinder head
^ Carefully apply a thin coat of sealant "D 454 300 02" to both edges of sealing surfaces between hydraulic chain tensioner and cylinder head - arrows - using a small screwdriver.
^ Operate all electric window switches again for at least one second in the "close" direction to activate the automatic one - touch function.
^ Set clock to correct time.
^ Perform adaptation of throttle valve control part.
^ Check DTC memory.
Notes: DTCs will be stored in the memory because connectors have been unplugged. Therefore, check and erase DTC memory after installing the engine.
Cylinder head, removing
^ Engine in vehicle
Notes:
^ Secure all hose connections with the correct hose clips (same as original equipment)
Refer to parts supplier.
^ All cable ties, which are opened or cut open when removing must be replaced in the same position when installing.
^ Obtain radio code on vehicles with coded radio.
^ With ignition switched off disconnect battery Ground strap.
^ Drain cooling system.
^ Remove intake manifold.
^ Disconnect coolant pipe from thermostat housing only.
^ Unbolt coolant pipe flange from cylinder head (left) and place it to one side.
^ Unplug connectors on ignition coils.
^ Unclip/release all pipes and hoses on the cylinder head and move clear.
^ Disconnect air hose - 1 - from upper air pipe.
^ Unbolt retainer for oil return line - 2 -.
^ Release hose - 4 - from upper air pipe (hose leads to turbocharger).
^ Remove bolts - 1 - and - 5 - for heat shield on back of cylinder head.
^ Remove bolts - 2 - and - 3 - for upper air pipe.
^ Remove upper air pipe and heat shield.
^ Unbolt turbocharger from exhaust manifold.
^ Remove ribbed belt and tensioning element.
^ Remove toothed belt guard (upper).
^ Set crankshaft to markings for TDC of No. 1 cylinder - arrows - by turning central bolt on crankshaft sprocket in direction of rotation.
^ Unscrew bolts (left arrows) and remove coolant expansion tank together with hoses.
^ Unscrew bolt (right arrow) and remove power steering reservoir. Do not disconnect the hoses.
^ Screw M5 x 55 stud - 1 - into toothed belt tensioning element.
^ Screw hexagonal nut - 2 - onto stud - 1 - using large washer - 3 -.
^ Tension pressure piston of tensioning element only until it can be secured 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.
^ Unbolt ignition coils.
^ Refer to Remove cylinder head cover.
Cylinder head, installing
Head Removal Sequence:
Notes:
^ Always replace cylinder head bolts when assembling.
^ Replace self-locking nuts.
^ Always replace bolts that are tightened to a specified angle.
^ If repairing, carefully remove any remains of gasket material from the cylinder head and cylinder block. Make sure that no long scores or scratches are made on the surfaces.
^ Carefully remove any remaining emery and abrasive material.
^ Remove new cylinder head gasket from packaging, just before installation.
^ Handle gasket extremely carefully. Damaging the silicone layer or the indented area will lead to leaks.
^ No oil or coolant must be allowed to remain in the blind holes for the cylinder head bolts in the cylinder head.
^ Ensure fuel hoses are tight.
^ Before positioning cylinder head, set crankshaft and camshaft to TDC of No. 1 cylinder.
^ Unscrew bolts - 1 - and - 2 - on turbocharger bracket (about 2 full turns each) to avoid stressing when installing the cylinder head.
^ Place cylinder head gasket in position.
^ Note position of centralizing pins in cylinder block - arrows -.
^ Check installation position of cylinder head gasket.
^ The Part No. should be legible from the intake side.
^ Place cylinder head in position.
^ Insert cylinder head bolts and tighten by hand.
^ Tighten cylinder head bolts in two stages in sequence shown as follows:
- Stage 1: 40 Nm
- Stage 2: additional 1/2 turn (180°) using rigid wrench (in two 1/4 turns (90°) if necessary).
Notes: It is not necessary to re - tighten cylinder head bolts after repairs have been performed.
^ Install turbocharger with new gasket and bolt bracket to cylinder block.
^ Install toothed belt (adjust valve timing).
Notes: Follow all instructions for removing and installing toothed belt.
^ Install cylinder head cover.
^ Installing ribbed belt and tensioning element.
^ After connecting battery terminals, enter anti - theft code for radio
Refer to Radio operating instructions
^ Close electric windows in front doors all the way to their top positions using electric switches.
^ Operate all electric window switches again for at least one second in the "close" direction to activate the automatic one - touch function.
^ Set clock to correct time.
^ Perform adaptation of throttle valve control part.
^ Check DTC memory.
Notes: DTCs will be stored in the memory because connectors have been unplugged. Therefore, check and erase DTC memory after installing the engine.
Electrical connections and routing:
Refer to Electrical Wiring Diagrams, Troubleshooting & Component Locations binder, Or equivalent