Cylinder head — removal and installation (Audi A4 B8)

Note: Replace the cylinder head mounting bolts. When performing installation work, replace the self-locking nuts, bolts that require additional tightening, and seals. rings and seals. The plastic linings included in the repair kit for protecting exposed valves may be removed immediately before installing the cylinder head. If the cylinder head or head gasket was replaced, the coolant and oil must be changed.

Disconnecting the cylinder head

Remove the arrow bolts. Loosen the cylinder head bolts in sequence. "1...10".

Cylinder head bolt tightening sequence

Tighten the cylinder head bolts in sequence. "1...10" as follows.



1. Pre-tighten to 40 Nm.

2/3. Tighten 90° with a regular wrench.

4. Pre-tighten the arrow bolts to 8 Nm.

5. Tighten the arrow bolts with a hard wrench by 90°.

Crankcase ventilation - sequence, tightening

Self-tapping bolts. When replacing the cylinder head, use only original bolts, as the cylinder head is supplied without threads for fastening the engine crankcase ventilation mechanism. Tapping is not permitted.



Tighten the system bolts. crankcase ventilation of the engine in sequence. "1...10" with a torque of 11 Nm.

Removal and installation the cylinder head

When reassembling, install all binders in the places where they were originally installed. Close the open channels of the intake circuit and system tightly. OG with corresponding plugs. For example, from the set of plugs for the "VAS 6122" engine, Remove the camshafts. Once the camshafts are removed, the crankshaft can no longer be rotated. Remove the downpipe/front muffler. Remove the seal from the front wall of the water drainage box. Remove the cover of the water drainage box.



Remove the vacuum hose "2" from the end wall of the water deflector box; to do this, disconnect the vacuum hose "3" on the rear side "arrow". Remove the rear coolant hoses to the cylinder head.



Disconnect the fuel supply line. hose "1" by pressing the locking ring. Disconnect hose "2" from the activated carbon canister.





Loosen clamp "1" and disconnect the air hose.



Disconnect connector "1" of the lambda probe "G39" and the lambda probe heater "Z19" and release the wiring. Disconnect connector "4" of the lambda probe after the "G130" neutralizer and the lambda probe heater 1 after the "Z29" neutralizer and release the wiring.



Unscrew nuts "1" from above and move the neutralizer back.





Remove the heat-insulating shield "arrows".



Unscrew the "arrow" nuts.



Remove the turbocharger from the studs in the direction of the arrow.



Disconnect connector "1" from the boost pressure sensor "G31" and set it aside. Loosen clamp "2" and remove the air hose.





Disconnect the following connectors.



2. Unfasten from knock sensor 1 "G61" and release.

3. From the intake manifold flap valve "N316", fuel pressure sensor "G247" and Hall sensor "G40".

4. From the injectors.

5. From the throttle body "J338".

6. From the intake air temperature sensor "G42".

Disconnect connector "2" and release the wire.



Unscrew the coolant line bracket "arrow". For better visualization, the installation position is shown with the engine removed.





Remove the inlet pipe branch pipe by unscrewing the fastening nut "1" and bolt "2".



Disconnect the hose clamp "arrow", remove the air duct hose and set it aside.



Disconnect connectors "1" and "3" from the "F22" oil pressure sensor and the "F378" oil pressure drop sensor. Remove the spark plugs using the "3122 B" spark plug wrench.





Unscrew the "arrow" bolts. Unscrew the cylinder head bolts in sequence. "1...10".



Check that all wires and cables are free! Pay attention to the tensioner bar and chain guide bar when lifting the cylinder head. Remove the cylinder head. Place the cylinder head on a soft pad (foam).

Installation

Caution! Risk of damage to the sealing surface. Carefully remove any remaining sealant from the cylinder head and cylinder block. Avoid creating long scratches or burrs. There should be no oil or coolant in the blind holes of the cylinder head bolts. Risk of a leaky cylinder head gasket. Carefully remove any remaining residue after sanding and grinding. To prevent damage to the silicone layer and the grooves of the cylinder head gasket, handle the gasket with particular care. When installing a replacement cylinder head, remove the plastic base to protect the exposed valves only when it comes into direct contact with the cylinder head. There is a risk of damage to the valves and piston crowns after working on the valve train. To ensure that no valves are touching the cylinder head during operation, carefully rotate the engine at least 2 revolutions. Replace any bolts that were overtightened. Replace all seals, gaskets and self-locking nuts. Consider different sealants for cylinder head sealing surfaces and bolts. Before installing a replacement cylinder head, lubricate the mating surfaces of the hydraulic lifters, rocker arms, and camshaft running surfaces with oil before installing the camshaft bearing housing. Hose fittings and air duct tubes and hoses syst. must be cleaned of oils and grease before installation. Secure all hose connections with hose clamps of the appropriate series.

Install the cylinder head gasket. Take into account the centering pins in the cylinder block "arrows". Take into account the installation. position of the cylinder head gasket, marking: the part number must be clearly visible from the intake side.



Make sure that the timing chain does not damage other components when turning the crankshaft. If the crankshaft has been turned, bring the piston of the first cyl. at TDC and again slightly turn the crankshaft back. Install the cylinder head. Insert the cylinder head mounting bolts and tighten them by hand. Tightening the cylinder head mounting bolts after repair work is not necessary. Turn the vibration damper with counter-support "T10355" to the "TDC" position "arrow". The notch on the vibration damper must be opposite the arrow mark on the lower timing chain cover.



Installation in reverse order. Install the camshafts. Install the upper drive chain cover. Change the oil. Replace the coolant. Install a catalytic converter. Install the downpipe/front muffler.

Compression check

Oil temperature min. 30°C. Battery voltage minimum 12.7 V. Remove the "arrow" engine cover.



Remove the lambda probe connector "1" from the holder. Unlock and simultaneously disconnect all connectors from the coils. Unscrew the mounting screws and remove the ignition coils. Remove the spark plugs with a 3122B spark plug wrench. Check the compression pressure with a compression tester and adapter "VAG 1763/6". Turn the starter until the compression gauge readings stop increasing.



Install spark plugs. Install ignition coils with output stages. When plug connections are disconnected, errors are written into the memory. After measuring, interrogate and, if necessary, erase the fault memory.

New, bar excess pressure	Wear tolerance limit, bar overpressure	Difference between cylinders, bar excess pressure
11,0—14,0	7,0	max 3.0