Cylinder Head, Servicing

Cylinder head, servicing

Checking Compression, Refer to Compression Check.

Note:
^ When installing an exchange cylinder head (with camshaft installed), the contact surfaces between the hydraulic lifters and the cam must be oiled before installing the cylinder head cover.
^ The plastic packing pieces for protecting the open valves must not be removed until immediately before installing the cylinder head.
^ If the cylinder head is replaced, all the coolant in the system must also be replaced.





1. Cap
^ Replace seal if damaged
2. 10 Nm
3. Cylinder head cover
4. Cylinder head cover gasket
^ Replace if damaged
^ Before installing gasket, coat transition between bearing cap/cylinder head with D 454 300 A2
^ Coat half-moon shaped surface with D 454 300 A2
5. Oil deflector
^ Note installation position: Above intake camshaft between No. 1 and No. 2 cylinders
6. Cylinder head
^ Check for distortion see Fig. 1
^ Reworking sealing surface, Refer to Valve train servicing; Fig 1.
^ Removing and installing See Below.
^ After replacing, completely replace engine coolant
7. Intake manifold gasket
^ Always replace
8. Cylinder head gasket
^ Always replace
^ Metal gasket
^ If replaced, completely replace engine coolant
^ Note installation position: Identification: Part No. must be readable from intake side
9. 25 Nm
^ For tensioner
10. Exhaust manifold gasket
^ Always replace
^ Note installation position
11. Cylinder head bolt
^ Always replace
^ Sequence when loosening and tightening, Removing and installing cylinder head.
^ Remove and install Polydrive cylinder head bolt with 3452.
12. Heat shield
13. 25 Nm
14. 10 Nm





Fig. 1 Checking cylinder head for distortion
Max. permissible distortion: 0.1 mm

Cylinder head, removing and installing





Special tools and equipment
^ VAG 1306 Drip tray
^ VAS 5024 Spring clip pliers
^ 3070 Guide pins & handle
^ VAG 1332 Torque wrench (40 to 200 Nm)

Engines with Polydrive cylinder head bolts:





^ 3452 Key

Requirements
^ The engine must be no more than warm to touch.
^ The pistons must not be positioned at TDC.

Work sequence
- Check whether a coded radio is installed. If so, obtain anti-theft coding.
- With ignition switched off disconnect battery Ground strap.
- Drain coolant.
- Separate fuel supply and fuel return lines at connection on fuel rail.

Note: The fuel system is under pressure. Place a cloth over the connection before the hoses are pulled off.

- Seal lines so that fuel system is not contaminated by dirt etc.
- Disconnect front exhaust pipe or catalyst from exhaust manifold.
- Remove toothed belt guard - upper part.
- Release tensioner and remove toothed belt from camshaft sprocket.
- Remove cylinder head cover.





- Loosen socket head bolts in sequence given and then remove completely.

Note: Use tool 3452 for Polydrive cylinder head bolts.

- Carefully lift off cylinder head.

Installing

Note:
^ There must not be any oil or coolant in the cylinder head bolt pockets in the cylinder head.
^ Only remove the new cylinder head gasket from its packing immediately before installing.
^ Handle the new gasket with extreme care. Damage will lead to leaks.

- Place a clean cloth in cylinders so that no dirt or emery cloth particles can get between cylinder wall and piston.

Note: Ensure that dirt and emery cloth particles do not get into the coolant.

- Carefully clean cylinder head and cylinder block sealing surfaces to ensure that no scores or scratches are formed (when using abrasive paper the grade must not be less than 100).
- Carefully remove metal particles, emery remains and cloths.
- Set No. 1 cylinder piston to top dead centre and then turn crankshaft back slightly.





- To centralize, thread guide pins from 3070 into holes for cylinder head bolts 8 and 10.
- Install new cylinder head gasket. Lettering (Part No.) must be readable.
- Install cylinder head, thread in 8 remaining cylinder head bolts and tighten by hand.
- Remove guide pins with removal tool from 3070 by turning removal tool counterclockwise until pins are free.
- Install remaining cylinder head bolts and tighten hand-tight.





- Tighten cylinder head in following tightening sequence:
- Pretighten all bolts to 40 Nm.
- Then tighten all bolts to 60 Nm.
- Then tighten all bolts 1/4 turn (90°) further using a rigid wrench.
- Then tighten all bolts again 1/4 turn (90°) further.

Note:
^ The rest of the assembly is basically a reverse of the dismantling sequence.
^ Installing toothed belt and adjusting timing, Refer to Timing Components.
^ Filling with new coolant, Refer to Cooling System.