Contents: Removal ↓ Installation ↓
Cylinder Head Bolt Tightening Sequence
Cylinder Block Gasket Marks
Removal and installation of the cylinder head is performed on a cold engine. The exhaust manifold is not removed. The cylinder head can be removed and installed without removing the engine.
The features of removing and installing the cylinder head of a diesel engine are given in subsection 2.6.1.2.
A defective cylinder head gasket can be determined by the following signs:
- loss of power;
- coolant leak. White plumes of exhaust gas when the engine is warm;
- oil leak;
- coolant in engine oil. Oil level does not decrease, but increases. Gray color of engine oil, foam bubbles on the oil level indicator, oil is liquid;
- engine oil in coolant;
- the coolant is bubbling violently;
- there is no compression in two adjacent cylinders.
Removal
1. Disconnect the negative (-) cable from the battery.
2. Disconnect the wires from the cylinder head:
- cO potentiometer plug;
- throttle potentiometer plug;
- multi-contact connection;
- idle speed control valve plug;
- cold start valve plug;
- lambda probe plug connection under the car, on the bracket of the attachments on the right;
- pressure sensor plug on the power steering housing, if available;
- oil pressure sensor plug on the left end side of the cylinder head;
- ground wire from the cylinder head cover and intake manifold.
3. Remove the engine harness through the intake manifold, having previously marked the position of the cable clamps with a felt-tip pen. Open the cable clamps or cut them off.
4. Remove all wires from the spark plugs.
5. Remove the throttle control cable from the throttle body and stop.
6. Remove the air hose at the connection points between the air filter and the throttle body, unscrew and remove the idle speed stabilization valve together with the bracket, remove the engine crankcase ventilation hose, remove the idle speed stabilization hose from the air filter housing and remove the air hose together with the idle speed stabilization valves.
7. Remove the vacuum hoses:
- on the intake air preheater throttle valve, activated carbon tank solenoid valve, Digifant control unit;
- on the brake booster check valve.
8. Remove the fuel supply line (black), cold start line and fuel distributor, having previously loosened the clamps. Before removing, place a rag underneath to collect the leaking fuel. Immediately plug the lines with suitable plugs. To do this, insert, for example, clean screws of a suitable diameter into the hoses.
9. Remove the fuel return line (blue) from the fuel distributor, after loosening the clamp.
10. Unscrew the generator support on the cylinder head.
11. Drain the coolant (see subsection 2.16.3).
12. Unscrew the coolant fittings on the cylinder head and, without removing the hoses, set them aside.
13. Unscrew the exhaust pipe from the exhaust manifold and cylinder head.
14. Remove the intake air heater air hose from the exhaust manifold housing.
15. Unscrew the exhaust manifold covers.
16. Unscrew the intake manifold.
17. Place the machine on supports.
18. Remove the engine compartment splash guard (see subsection 2.4).
19. Unscrew the exhaust pipe from the exhaust manifold. Lower the exhaust system slightly and hang it on a wire (see subsection 2.19.1).
20. Remove the upper timing belt cover.
21. Loosen the timing belt and remove it from the top of the camshaft (see subsection 2.5.1.1).
22. Remove the camshaft timing gear (see subsection 2.7).
23. Unscrew the timing belt tension roller.
24. Unscrew the bolts securing the rear timing belt cover.
25. Unscrew the cylinder head cover. Remove the oil separator.
26. Remove the cylinder head cover seals.
27. Unscrew the cylinder head bolts with a socket wrench, for example (HAZET990Slg-12).
Attention! Bolts must be loosened in reverse order of numbering from 10 to 1 (see Fig. Cylinder Head Bolt Tightening Sequence). The cylinder head must be sufficiently cool before removal (room temperature), otherwise, the removed cylinder head may become warped.
28. Check that all pipes and hoses leading to the cylinder head have been removed.
29. Remove the cylinder head and place it on two wooden blocks. Before removing, press the rear toothed belt cover slightly.
30. Remove the cylinder head gasket.
Installation
1. Before installation, clean the mating surfaces of the cylinder head and cylinder block from gasket residues using a suitable scraper. Make sure that dirt does not get into the cylinder block holes. Cover the holes with a rag.
2. Check for oil in the holes for the cylinder head mounting screws, remove if necessary. To do this, insert a clean rag into the holes and collect the oil.
Caution: If oil remains in the holes, the cylinder block may be damaged when tightening the bolts.
3. Check the cylinder head for flatness with a steel ruler. Flatness is checked with a steel ruler and a petal feeler gauge over the entire surface of the cylinder head. Unevenness should not exceed 0.1 mm.
Attention! If the cylinder head sealing surfaces are to be modified, the minimum permissible height dimension must not be reduced (see subsection 2.10.3).
4. Cylinder heads with gaps between valve seats and valve seat rings, as well as the first thread runs under the spark plug thread, can be used further without reducing service life and overhauling, if the gaps do not exceed the maximum permissible value a = max 0.5 mm.
5. Always replace the cylinder head gasket.
6. The signature "oben" should point to the cylinder head. Install the cylinder head gasket without sealant so that no holes are covered.
7. Turn the crankshaft by the belt pulley so that all pistons are at approximately the same height.
8. Install the cylinder head, paying attention to the cylinder block guide pins. If necessary, install new guide pins in both outer holes on the inlet side. Make sure that the camshaft is in the TDC position for cylinder 1 (see Fig. subsection 2.5.2.1).
9. Install all 10 cylinder head bolts with washers and tighten finger tight. Always replace cylinder head bolts.
Caution! Tighten the cylinder head bolts with great care. Before tightening the bolts, check the accuracy of the torque wrench. Tighten the cylinder head bolts on a cold engine.
10. The cylinder head bolts are tightened with a torque wrench in the sequence from 1 to 10 in two steps: first with a force of 40 N·m, and then with 60 N·m. After this, additional tightening is performed with a rigid wrench: 1/2 turn (180°). Additional tightening of 90° x 2 (two times 90° each) is allowed.
11. When tightening the cylinder head bolts, you can evaluate the rotation angle. Place the handle of the wrench along the engine and turn the wrench in one movement until the handle is positioned across the engine (1/4 turn, 90°). Turn the wrench further - until the handle is positioned again along the engine.
Caution! Tightening the cylinder head bolts on a warm engine during maintenance or after repairs is not permitted.
Attention! When replacing the cylinder head with the camshaft installed, it is necessary to lubricate the contact surfaces between the plate tappets and the surface of the cams with oil after installing the cylinder head.
12. Set the crankshaft to the TDC position for cylinder 1.
13. Screw on the rear timing belt cover.
14. Screw on the camshaft gear and timing belt tensioner roller.
15. Install the timing belt.
16. Install the cylinder head cover with the oil separator and new seals and tighten to 10 Nm.
17. Install the upper timing belt cover.
18. Bolt the generator support to the cylinder head.
19. Tighten the V-belt (see subsection 2.12.1).
20. Install the exhaust pipe onto the exhaust manifold (see subsection 2.19.1).
21. Install the engine compartment splash guard.
22. Remove the car from the supports.
23. Screw the exhaust pipe to the exhaust manifold and cylinder head.
24. Screw on the exhaust manifold cover.
25. Place the intake air heating air hose onto the casing.
26. Install the air hose between the air cleaner and the throttle body along with the idle speed control valve.
27. Attach the throttle control cable to the throttle valve and to the stop.
28. Route the engine wiring harness through the intake manifold.
29. Connect the electrical wiring:
- cO potentiometer plug;
- throttle potentiometer plug;
- multi-contact connection of injection valves;
- idle speed control valve plug;
- cold start valve plug;
- lambda probe plug connection under the car, on the bracket of the attachments on the right;
- power steering pressure sensor plug, if equipped;
- oil pressure sensor plug on the left end side of the cylinder head;
- ground wire from the cylinder head cover to the intake manifold.
Attention! Secure the electrical wires in their original places with new cable clamps.
30. Put on the spark plug wires.
31. Attach the vacuum hoses:
- on the intake air preheater throttle valve, activated carbon tank magnetic valve, Digifant control unit;
- on the brake booster check valve.
32. Place the fuel supply line (black) onto the cold engine start and fuel distribution valve and secure with clamps.
33. Place the fuel return line (blue) onto the fuel distributor and secure with a clamp.
34. Screw the coolant nipple with hoses to the cylinder head.
35. Fill with coolant. Always replace coolant.
36. Connect the negative (-) wire to the battery. Enter the anti-theft code, program the radio stations and set the time on the clock.
Attention! Connect the battery only when the ignition is off, otherwise the fuel injection system control unit will fail.
37. Check the engine oil level. If the cylinder head gasket was defective, replace the engine oil and filter.
38. Warm up the engine to operating temperature. Check the coolant level and tightness of connections again.
39. Check the ignition timing (see subsection 2.14.6).
40. Check idle speed and CO content (see subsection 2.18.1).
41. Check the compression pressure (see subsection 2.11).
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