Caution! A lifting mechanism must be used to remove the cylinder head. A new gasket must be used when installing the cylinder head. A new bolt must be used to secure the camshaft bearing that controls the intake valves.
Removal
Cylinder head
1 – cylinder head; 2 – bearing cover; 3 – vortex chamber; 4 – swirl chamber mounting nut; 5 – valve guides; 6 – oil deflector caps; 7 – valve seats; 8 – cylinder head cover; 9 – cylinder head cover gasket
Elements of the auxiliary drive belt tensioning mechanism
1 – plastic cover; 2 – bolt; 3 – intermediate pulley; 4 – bolt; 5 – radiator fan; 6 – bolts; 7 – shock absorber strut of the tensioning mechanism; 8 – springs; 9 – plastic plug; 10 – bolt; 10a – bolt of a different design; 11 – bushing; 12 – tension mechanism; 12a – tensioning mechanism of a different design; 13 – gasket
Tightening sequence of cylinder head bolts on a 4-cylinder diesel engine
Tightening sequence of cylinder head bolts on a 5-cylinder diesel engine
Tightening sequence of cylinder head bolts on a 6-cylinder diesel engine
Fuel line connections to the fuel filter
Hose connection point to the exhaust gas recirculation system valve
Using the special tool (1) to release the retaining clip (2) from the connection of the coolant elbow to the oil cooler
1. The cylinder head is removed on a cold engine together with the manifolds.
2. Remove the ground cable from the battery.
3. Open the hood and place it in a vertical position.
4. Drain the engine oil from the engine.
5. Remove the camshaft.
6. Remove the fuel injectors.
7. Remove the radiator.
8. Remove the auxiliary drive belt tensioner mechanism (see fig. Elements of the auxiliary drive belt tensioning mechanism).
9. Remove the plastic plug, unscrew the bolt and remove the auxiliary drive belt idler pulley.
10. Remove the bolts and remove the radiator fan pulley.
11. Unscrew the bolts and remove the tensioner shock absorber strut.
12. Using pliers, remove the tensioner spring.
13. Remove the plastic plug, unscrew the bolt and remove the auxiliary drive belt tensioner.
14. On non-turbocharged models, remove the air cleaner cover, air intake tube and air cleaner element.
15. On turbocharged models, remove the air intake duct from the turbocharger.
16. Unscrew the turbocharger bracket hanger.
17. Unscrew the nut and disconnect the turbocharger oil return line from the cylinder head.
18. Place a clean rag under the fuel line connection to the fuel filter. Then unscrew the nuts and disconnect the fuel lines (see Fig. Fuel line connections to the fuel filter). Close the ends of the pipes with plugs.
19. Unscrew the fuel filter from the cylinder head.
20. Unscrew the engine oil dipstick tube from the cylinder head.
21. Remove the hose from the EGR valve (see Fig. Hose connection point to the exhaust gas recirculation system valve).
22. Working underneath the vehicle, remove the bolts securing the exhaust support bracket to the transmission, then remove the bolts and bracket from the exhaust system.
23. Disconnect the exhaust pipe from the intake manifold.
24. Using the special tool, disconnect the retaining clip from the coolant elbow connection to the oil cooler (see Fig. Using a special tool to release the retaining clip from the coolant elbow connection to the oil cooler).
25. Unscrew the elbow pipe from the oil cooler, then disconnect it from the connector.
26. Unscrew the nuts securing the supply bus to the glow plugs.
27. Remove the intake manifold.
28. Remove the upper timing chain guide.
29. Through the hole in the cylinder head, unscrew the two bolts securing the cylinder head to the timing chain cover (see Fig. Location of bolts securing the drive chain cover to the cylinder head).
30. Check that all hoses and electrical connectors are disconnected from the cylinder head.
31. Gradually and evenly unscrew the cylinder head mounting bolts in the reverse order shown in the figures Sequence of tightening the cylinder head mounting bolts on a 4-cylinder diesel engine, Sequence of tightening the cylinder head mounting bolts on a 5-cylinder diesel engine, Sequence of tightening the cylinder head mounting bolts on a 6-cylinder diesel engine.
32. Remove the cylinder head bolts, noting their locations as bolts of different lengths are used.
33. Attach lifting gear to the eyes located on the left front side of the cylinder head and on the right rear side of the exhaust manifold and remove the cylinder head from the engine.
34. Remove the cylinder head gasket.
Preparing for installation
Measuring the length of the cylinder head bolt
1. The mating surfaces of the engine head and cylinder block must be thoroughly cleaned of old gasket residue and carbon deposits using a plastic or wooden scraper. It is also necessary to clean the upper parts of the pistons. When cleaning, eliminate the possibility of cleaning products getting into the oil channels of the cooling system. Thoroughly clean the inner surfaces of the cylinders.
2. Check the mating surfaces of the engine head and cylinder block for defects. Minor damage can be repaired by mechanical treatment. Also, using a metal ruler and feeler gauge, check the flatness of the mating surfaces.
3. Clean the bolt holes in the block. Driving a bolt into an oil filled hole can cause the block to burst due to hydraulic pressure.
4. Measure the length of the cylinder head bolts (see fig. Measuring the length of the cylinder head bolt). If the bolt length exceeds the permissible limits, the bolts must be replaced as a set.
Installation
1. Check that the timing marks on the camshaft and crankshaft are aligned with the pointers.
2. Check that the two guide pins are installed in the cylinder block and install the cylinder head gasket.
3. Using a lifting mechanism, install the cylinder head.
4. Lubricate the cylinder head mounting bolts with engine oil, insert them into the head and tighten by hand.
5. Tighten the cylinder head bolts gradually and sequentially in several stages (see fig. The sequence of tightening the cylinder head mounting bolts on a 4-cylinder diesel engine, the sequence of tightening the cylinder head mounting bolts on a 5-cylinder diesel engine, The sequence of tightening the cylinder head mounting bolts on a 6-cylinder diesel engine).
6. Screw in and tighten to the specified torque the bolts securing the drive chain cover to the cylinder head.
7. Install the upper chain guide.
8. Install the intake manifold.
9. Install the supply bus onto the glow plugs and secure with nuts.
10. Soak a new sealing ring in clean coolant and install it on the elbow. Install the elbow on the oil cooler and secure with the retaining clip.
11. Connect the exhaust pipe to the exhaust manifold.
(Article was borrowed from the website MercedesMan)
12. Install the exhaust system mounting bracket to the gearbox and secure with bolts.
13. Further installation is carried out in the reverse order of removal, taking into account the following points.
14. Install the auxiliary drive belt tensioner in the reverse order of removal.
15. Fill the engine cooling system with coolant.
16. Fill the engine with motor oil.