Cylinder head
![](https://www.mercedesman.ru/img/e-class/0726.jpg)
1 – a head of the block of cylinders; 2 – a cover of the bearing of a camshaft; 3 - oil supply pipe; 4 – laying of a head of the block of cylinders; 5 – a cover of a head of the block of cylinders; 6 - partition; 7 – laying of a cover of a head of the block of cylinders; 8 - valve guide; 9 - valve seat; 10 – technological plug; 11 - hairpin
Loosening the cylinder head bolts
![](https://www.mercedesman.ru/img/e-class/0727.jpg)
Removing
The cylinder head is removed on a cold engine along with the intake and exhaust manifolds.
The location of the intake manifold mounting bolts on engines with a fuel injection system
![](https://www.mercedesman.ru/img/e-class/0728.jpg)
Removing the coolant supply hose from the fitting at the rear of the cylinder head
![](https://www.mercedesman.ru/img/e-class/0729.jpg)
Disconnecting the electrical connector from the coolant temperature sensor
![](https://www.mercedesman.ru/img/e-class/0730.jpg)
Arrangement of bolts of fastening of a cover of a driving chain to a head of the block of cylinders
![](https://www.mercedesman.ru/img/e-class/0731.jpg)
1. Remove the ground wire from the battery.
2. Open and place the hood in a vertical position.
3. Drain the coolant from the cooling system.
4. Remove the air filter.
5. Remove the camshaft sprocket and upper chain guide.
6. Remove the auxiliary drive belt.
7. Disconnect the exhaust pipe from the exhaust manifold.
8. Remove the nuts securing the dipstick tube to the exhaust manifold.
9. Remove the accelerator cable from the throttle lever.
10. Unscrew the strut from the intake manifold. On engines with a carburetor, unscrew the bolt securing the strut to the manifold. On engines with a fuel injection system, unscrew the two bolts and remove the throttle return spring (see fig. The location of the intake manifold mounting bolts on engines with a fuel injection system).
11. Loosen the clamp and remove the coolant supply hose to the heater from the fitting at the rear of the cylinder head (see fig. Removing the coolant supply hose from the fitting at the rear of the cylinder head).
12. Disconnect the electrical connector from the crankshaft angle sensor and the left four-pin connector from the ignition control unit.
13. Unscrew a nut and disconnect a wire from a clip on fastening of a diagnostic socket.
14. Unscrew the diagnostic connector, then disconnect the gray connector from the back of the socket.
15. Disconnect the electrical connectors from the sensors located on the cylinder head and intake manifold (see fig. Disconnecting the electrical connector from the coolant temperature sensor).
16. Disconnect the vacuum hoses from the cylinder head and intake manifold.
17. Remove the brake booster vacuum hose from the intake manifold fitting.
18. On models with a fuel injection system, relieve pressure in the fuel line.
19. Disconnect the fuel supply and return hoses from the carburetor or fuel pressure regulator. Close the ends of the hoses with appropriate plugs.
20. On models with an air conditioning system, unscrew the A/C pipe bracket from the cylinder head.
21. Remove the generator.
22. Remove the top three bolts securing the timing chain cover to the cylinder head (see fig. Arrangement of bolts of fastening of a cover of a driving chain to a head of the block of cylinders).
23. Check that all wires and hoses are disconnected from the cylinder head.
24. Working in reverse order of tightening (see fig. Cylinder head bolt tightening sequence), loosen the cylinder head bolts 1/3 turn each pass until the bolts are completely loose.
25. Remove the cylinder head from the cylinder block.
26. Remove the cylinder head gasket.
Preparing the head for installation
Measuring the length of the cylinder head bolt
![](https://www.mercedesman.ru/img/e-class/0732.jpg)
The maximum allowable bolt length is 122.0 mm.
1. The mating surfaces of the head and cylinder block must be perfectly clean. Use a hard plastic or wooden scraper to clean them. Be careful when cleaning as aluminum alloy is very easy to damage. Check that carbon deposits do not get into the oil and water channels. This is especially important for the lubrication system, as deposits can block the oil supply to engine components. If necessary, clean the channels, check the mating surfaces of the head and cylinder block for nicks, deep scratches and other damage. If the defects are small, they can be removed by machining. In case of significant defects, the parts must be replaced.
2. Using a metal ruler and feeler gauge, check the flatness of the mating surfaces.
3. Clean the bolt holes in the cylinder block. Screwing a bolt into oil-filled holes can rupture the block due to hydraulic pressure.
4. Measure the length of the bolts from the base of the head (see picture). If the bolt length exceeds the allowable limits, replace all the bolts in the kit.
Installation
Attention! When installing the cylinder head, a new gasket must be used. Remove the gasket from its sealed package just before installing it on the cylinder block.
Cylinder head bolt tightening sequence
![](https://www.mercedesman.ru/img/e-class/0733.jpg)
1. Install the manifolds to the cylinder head.
2. Check that the timing marks on the crankshaft and camshaft are aligned with the pointers.
3. Check that the new cylinder head gasket is the same type as the original and that the TOP or OBEN·markings are facing up. Install the cylinder head gasket on the guide pins on the cylinder block.
4. Install the cylinder head on the guide pins.
5. Apply a light coat of engine oil to the threads and base of the bolt heads. Insert the bolts into the cylinder head and hand tighten at this stage.
6. Gradually and sequentially tighten all the cylinder head bolts to the required torque and in several stages in the sequence shown in the figure.
7. Screw in the three bolts securing the upper part of the drive chain cover to the cylinder head.
8. Install the generator.
9. If equipped, install the air conditioning pipe bracket to the cylinder head.
10. Connect the supply and return fuel hoses.
11. Connect the brake booster vacuum hose to the intake manifold fitting.
12. Connect to a head of the block of cylinders all earlier removed hoses and electric sockets.
13. Connect the coolant supply hose to the heater to the rear of the cylinder head.
14. Install the mounting bracket to the intake manifold.
15. Connect and, if necessary, adjust the accelerator cable to the throttle lever.
16. Screw on the pipe for the dipstick to measure the oil level.
17. Connect the exhaust pipe to the exhaust manifold.
18. Install the auxiliary drive belt.
19. Install the upper chain guide and camshaft sprocket.
20. Install the air filter.
21. Fill the cooling system with coolant.
22. Connect the battery ground wire.