Installing the valve in the cylinder head
Installing the lower spring seat
1. Lubricate the valve stems with clean engine oil and insert them into their places. Install the valves in the places where they were ground.
2. Install the spring seat. Dip the valve stem seal into fresh engine oil and install it over the valve stem, being careful not to damage its working edges. To protect the working edges of the valve stem seal, you can wrap the end of the valve stem with adhesive tape before installing.
3. Install the valve spring and spring retainer.
4. Using a special tool, compress the valve spring and install the crackers in the recesses of the valve stem and lubricate them. Remove the spring compressor. Repeat this operation on the remaining valves.
5. Using a hammer and a wooden block, tap the end of the valve stem to ensure that all valve components are firmly seated in place.
6. Install the thermostat housing onto the cylinder head.
7. Screw in the spark plugs.
8. Install the camshaft and valve train with hydraulic tappets.
9. Install the intake and exhaust manifolds.
10. Install the cylinder head (see subsection 3.13.3).
6-cylinder SOHC petrol engines
Lubricating the oil seal
Installing a plastic sleeve on the valve stem to protect the working edges of the oil deflector cap
1. Lubricate the valve stems with clean engine oil and insert them into their places. Install the valves in the places where they were ground.
2. Install the spring seat. Dip the valve stem seal into fresh engine oil and install it over the valve stem, being careful not to damage its working edges. To protect the working edges of the valve stem seal, you can wrap the end of the valve stem with adhesive tape before installing.
3. Install the valve spring and spring retainer.
4. Using a special tool, compress the valve spring and install the crackers in the recesses of the valve stem and lubricate them. Remove the spring compressor. Repeat this operation on the remaining valves.
5. Using a hammer and a wooden block, tap the end of the valve stem to ensure that all valve components are firmly seated in place.
6. Install the thermostat housing onto the cylinder head.
7. Screw in the spark plugs.
8. Install the camshaft and valve train with hydraulic tappets.
9. Install the intake and exhaust manifolds.
10. Install the cylinder head (see the corresponding description in subsection 4.12).
6-cylinder DOHC petrol engines
Using a tubular mandrel to install the valve stem seal
Installing the inner valve spring
1. Lubricate the valve stems with clean engine oil and insert them into their places. Install the valves in the places where they were ground.
2. Install the spring seat. Dip the valve stem seal into fresh engine oil and install it over the valve stem, being careful not to damage its working edges. To protect the working edges of the valve stem seal, you can wrap the end of the valve stem with adhesive tape before installing.
3. Install the valve spring and spring retainer. Early models had two springs per valve. Later models with a single conical spring, the larger diameter spring should be on the cylinder head side.
4. Using a special tool, compress the valve spring and install the crackers in the recesses of the valve stem and lubricate them. Remove the spring compressor. Repeat this operation on the remaining valves.
5. Using a hammer and a wooden block, tap the end of the valve stem to ensure that all valve components are firmly seated in place.
6. Install the thermostat housing onto the cylinder head.
7. Screw in the spark plugs.
8. Install the camshaft and valve train with hydraulic tappets.
9. Install the intake and exhaust manifolds.
10. Install the cylinder head (see the corresponding description in subsection 5.15).
Diesel engines
Installing the outer valve spring
Installing the upper spring seat
Installing crackers on the valve stem
1. Lubricate the valve stems with clean engine oil and insert them into their places. Install the valves in the places where they were ground.
2. Install the spring seat. Dip the valve stem seal into fresh engine oil and install it over the valve stem, being careful not to damage its working edges. To protect the working edges of the valve stem seal, you can wrap the end of the valve stem with adhesive tape before installing.
3. Install the valve spring and spring retainer.
4. Using a special tool, compress the valve spring and install the crackers in the recesses of the valve stem and lubricate them. Remove the spring compressor. Repeat this operation on the remaining valves.
5. Using a hammer and a wooden block, tap the end of the valve stem to ensure that all valve components are firmly seated in place.
6. Install the thermostat housing onto the cylinder head.
7. Screw in the glow plugs.
8. Install the camshaft and valve train with hydraulic tappets.
9. Install the intake and exhaust manifolds.
10. Install the cylinder head (see the corresponding description in subsection 6.12).
Original source of information (MercedesMAN.ru)