Contents: Removal ↡ Installation ↡
Cylinder Head Bolt Locations
Remove the cylinder head only when the engine is cool. The exhaust manifold is not removed.
A defective cylinder head gasket can be identified by one or more of the following signs:
- loss of power;
- coolant leak, white exhaust gas when engine is hot;
- oil leak;
- coolant in engine oil, oil level does not decrease but increases, clumps of foam on the oil level indicator; gray color, dilution of motor oil;
- engine oil in coolant;
- the coolant is bubbling violently;
- lack of compression in two adjacent cylinders.
Removal
1. Lift the hood.
2. Disconnect the battery ground cable.
Attention! This will erase the radio's anti-theft code.
3. Remove the air filter.
4. Remove the cross pipe and air cleaner suction hose.
5. Drain the coolant.
6. Remove the radiator.
7. Loosen the ribbed V-belt and remove it.
8. Remove the ribbed V-belt tensioner.
9. Clamp the fuel lines into the fuel filter holder using hose clamps.
Attention! To facilitate subsequent installation, mark the fuel lines with adhesive tape. Remove any spilled fuel with a rag.
10. Unscrew the two bracket mounting bolts and remove the bracket with the fuel filter.
11. Unscrew the holder (62) of the oil level gauge guide pipe.
12. Remove the hose from the exhaust recirculation valve (arrow) leading to the air duct housing.
13. Remove the hose between the exhaust recirculation valve and the inlet pipe.
14. Unscrew the side support (5) of the gearbox (1) and the exhaust pipe (2).
15. Unscrew the front exhaust pipe from the manifold.
16. Remove the injectors.
17. Remove the clamp (91) of the heating supply line using a homemade hook (01).
18. Unscrew the pipe branch (93) from the oil filter and remove it from the branch pipe (89).
19. Unscrew the electrical wires from the glow plugs, having previously marked them with adhesive tape.
20. Remove the 36-pin connector (X26/2).
21. Remove the intake manifold.
22. Remove the cylinder head cover.
23. Set the engine to the TDC position of the first cylinder ignition.
24. Disassemble the chain tensioner.
25. Remove the camshaft, marking the position of the timing chain and timing gear with varnish or a graver.
26. Knock out two pins (221) and (222) using an M6 threaded pin and a punch.
27. If you don't have such a tool, you can remove the pins using a ten-tooth chain sprocket (the length of the square is 1/2 inch) and an M6 bolt, which is approximately three times the length of the sprocket. To do this, screw a lock nut onto the M6 bolt, then install a spacer washer on it. Put the sprocket on the pin, screw the M6 bolt into the pin thread and tighten the lock nut until it touches the sprocket. The spacer washer serves to improve the fit of the surfaces. Pull out the pin, holding the bolt head with a spanner and simultaneously turning the lock nut with an open-end wrench relative to the sprocket.
28. Remove the control chain guide rail.
29. Remove the two M8 cylinder head bolts using a long socket wrench SW 6.
30. Remove the cylinder head bolts in the reverse order of their numbering, i.e. from 18 to 1 (see fig. Cylinder head bolt locations). In this case, first unscrew all the bolts by 1/2 turn and then unscrew them completely, using a socket wrench attachment, for example, HAZET 2751.
31. Raise the cylinder head, for example with a crane. The attachment points for the lifting cable are the eye at the front left and the exhaust manifold outlet at the rear right.
Installation
1. Clean the sealing surface from the sealant residues using a suitable scraper. Make sure that dirt does not get into the holes of the engine block. Cover the holes with a rag.
Caution! The cylinder head bolt holes must not be clogged with oil or coolant residue. Blow out the holes with compressed air or clean them with a screwdriver wrapped in a rag and suck out the liquid. Otherwise, when tightening new bolts, pressure will build up, which can lead to cracks in the engine block or incorrect bolt tightening torque.
2. Check the flatness of the engine block.
3. Place a new cylinder head gasket without sealant on the degreased sealing surface so that the holes are not covered.
4. Clean the sealing surface of the cylinder head.
5. Check the flatness of the cylinder head.
6. Install the cylinder head.
7. Measure the length (L) of the cylinder head bolts. If the maximum length is exceeded (see table Cylinder Head Bolts), do not use such bolts under any circumstances.
8. Lubricate the threads and the surface adjacent to the bolt head with engine oil. Check the bolts for cracks and replace if necessary. Screw the bolts into the cylinder head and tighten by hand (see table Cylinder Head Bolt Locations).
Caution! Cylinder head bolts must be installed without spacers. Tighten the bolts thoroughly. Check the accuracy of the torque wrench beforehand.
The cylinder head bolts are tightened in sequence from 1 to 18 in four stages (see fig. Cylinder head bolt locations).
Attention! The cylinder head bolts at each stage are tightened in sequence from 1st to 18th.
First step: using a torque wrench with a torque of 15 Nm.
Second stage: using a torque wrench with a torque of 35 Nm.
Step three: Using an open-end wrench, tighten the bolts in the same direction by 90°.
Caution! At this point, pause for 10 minutes before tightening the bolts. Then continue tightening the bolts without loosening them.
Step 4: Use an open-end wrench to tighten the bolts another 90°.
Caution: When tightening the bolts, hold the wrench handle along the engine and turn it in one motion until the handle is across the engine (1/4 turn = 90°).
9. Install elastic washers on the two M8 bolts (a) at the front of the cylinder head and tighten with a long socket wrench SW6 to a torque of 25 Nm.
10. Install the control chain guide rail, insert the pins, having previously lubricated their flanges with a sealing compound, for example, Mercedes-001 589 2520.
11. Install the camshaft.
12. Install the chain tensioner.
13. Set the engine to the TDC ignition position and check the position of the camshaft.
14. Install the cylinder head.
15. Install the intake manifold.
16. Install the 36-pin connector.
17. Screw in the glow plug wires.
18. Install the pipe elbow with a new o-ring and screw the elbow to the air filter.
Caution! The O-ring can be dipped in coolant to improve installation. Never use grease or oil.
19. Install the heating supply line and attach the retaining clamps.
20. Tighten the front exhaust pipe to the manifold with a torque of 25 Nm.
21. Tighten the gearbox bracket and front exhaust pipe to a torque of 25 Nm.
22. Install the hose from the exhaust gas recirculation valve to the air duct body, as well as the hose between the recirculation valve and the intake pipe.
23. Screw in the dipstick guide tube holder.
24. Install the fuel filter with the holder and tighten it to the cylinder head with a torque of 25 Nm.
25. Screw the fuel lines with new sealing gaskets to the fuel filter. Remove the hose clamps.
26. Install the ribbed V-belt tensioner.
27. Apply and tighten the ribbed V-belt.
28. Install the radiator.
29. Install the air cleaner cross pipe and air intake hose.
30. Install the air filter.
31. Fill with coolant.
32. Connect the ground (–) wire to the battery.
33. Set the clock.
34. Set the radio anti-theft code.
Caution: If the cylinder head gasket was defective, replace the engine oil and oil filter.
35. Warm up the engine to operating temperature and check the tightness of all connecting elements.
Caution! Tightening the cylinder head bolts is prohibited.
36. Finally, press the engine hood release button on the left bracket.
Cylinder head bolts
| Thread diameter | Length for new installation | Maximum length |
| M 10 | 80.0 mm | 83.6 mm |
| M 10 | 102.0 mm | 105.6 mm |
| M 10 | 115.0 mm | 118.6 mm |
Cylinder Head Bolt Locations
| Bolt size | Hole No |
| M 10–80 | 3, 5, 11, 13 |
| M 10–102 | 2, 4, 6, 8, 10, 12, 14, 16, 18 |
| M 10–115 | 1, 7, 9, 15, 17 |
| M 8-30 | a (chain case area) |
| M 8–80 | b (fuel filter) |