A burnt or defective cylinder head gasket is determined by the following signs:
- reduction in engine power;
- decrease in coolant level - white steam comes out of the exhaust pipe;
- decrease in engine oil level;
- the presence of coolant in the engine oil: the oil turns gray and foams. At the same time, the oil level rises;
- the presence of engine oil in the coolant;
- intensive release of bubbles from the coolant;
- reduction of compression in two adjacent engine cylinders.
Warnings: When installing the block head, you must use new mounting bolts.
All clamps and clamps that are damaged or cut during removal must be replaced with new ones when installing the head of the block.
When installing a new head with the camshafts installed, the contact surfaces between the camshaft cams and the valve lifters must be lubricated with engine oil.
The plastic caps to protect the open valves must not be removed before the block head is installed.
When replacing the block head, the cooling system must be filled with fresh coolant.
Before removal of a head of the block of cylinders be convinced that all hoses, pipelines and electric sockets are disconnected from it.
Left cylinder head
Withdrawal
Set the piston of the first cylinder to TDC.
Make sure the engine is cold. Otherwise, let it cool down.
Turn off the ignition and disconnect the wire «masses» from the battery.
Drain the coolant.
Remove the left front exhaust pipe.
Remove the toothed belt from the pulleys.
Remove the rear toothed belt cover.
Loosen the power steering pipe bracket bolt.
Mark the high-voltage wires with numbers, remove them from the spark plugs of 4-6 cylinders and take them aside.
Loosen the clamp, remove the hose from the cooling system pipe and unscrew the pipe mounting bolt.
Turn out bolts of fastening of a flange of a pipe of the cooling system to a back part of a head of the block of cylinders, supporting a pipe.
Disconnect from a head of the block of cylinders all electric sockets and take them aside.
Pic. 3.1–82. Arrangement of bolts of fastening of the left cover of a head of the block of cylinders
Turn out bolts and remove a cover of a head of the block of cylinders (see fig. 3.1–82).
Remove the oil deflector.
Pic. 3.1–84. The sequence of tightening the bolts of the left and right cylinder heads
In the reverse order to tightening, gradually loosen and then completely unscrew the cylinder head bolts (pic. 3.1–84).
Remove the cylinder head and place it on a soft base.
Preparing the left head for installation
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. Make sure that carbon deposits do not get into the channels of the lubrication and cooling system. This is especially important for the lubrication system, as deposits can block the oil supply to engine parts. Clean channels if necessary.
Check the mating surfaces of the head and cylinder block: they should not have notches, deep scratches and other damage. Small defects can be eliminated by machining. In case of significant defects, the parts must be replaced.
Using a metal ruler and feeler gauge, check the flatness of the mating surfaces.
If the flatness deviation exceeds 0.1 mm, the head must be reground. Cylinder head height
Pic. 3.1–85. Place of measuring the height of the cylinder head
A (pic. 3.1–85) after machining should be at least 132.75 mm for a six-cylinder engine.
Clean the bolt holes in the block. Screwing a bolt into an oil-filled hole may rupture the block due to hydraulic pressure.
Pic. 3.1–86. The location of the plug in the front end of the cylinder head
The cylinder head supplied as spare parts can be used on either the left or right side. In this case, the plug at the end of the head must be located on the front side of the head (pic. 3.1–86). When installing the plug, apply sealant AMW 188 001 02 to its outer surface. Install the plug flush with the end face of the cylinder head.
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
Replace the cylinder head bolts.
When installing the cylinder head, it is necessary to replace with new self-locking nuts and bolts, which were tightened by tightening to a certain angle, as well as sealing rings and gaskets.
A new cylinder head gasket must be removed from the packaging immediately before installation.
Install the gasket on the guide pins, while the inscription "oben" should point towards the head.
If work has been done on the valve train, turn the crankshaft two full turns by hand to make sure the pistons do not hit the valves.
Pic. 3.1–52. The location of the large holes of the fixing plates on the camshaft pulleys
Before installing the cylinder head, set the piston of the first cylinder and the camshaft to TDC on the compression stroke. In this case, the large holes of the fixing plates on the camshaft pulleys must be directed towards each other (see fig. 3.1–52).
Pic. 3.1–53. Location of set screw 3242 to fix the crankshaft
Lock the crankshaft in this position by unscrewing the ignition timing sensor from the cylinder block and screwing in set screw 3242 instead (see fig. 3.1–53).
Insert the cylinder head bolts and tighten by hand.
In the sequence shown in Figure 3.1–84, tighten the cylinder head bolts in two stages:
- 1st - tighten with a torque of 60 Nm;
- 2nd - tighten by an angle of 180°.
In the future, additional tightening of the cylinder head bolts is not required.
Install intake manifold.
Install the toothed belt and adjust its tension.
Install poly V-belt.
Install the exhaust pipe and check that the exhaust system parts are installed correctly.
Fill with coolant.
Connect wire «masses» to the battery.
Turn on the radio and enter the code into it.
Raise the windows with the power windows up to the stop. Then press all power window switches again for at least 1 second to the closed position to activate the power window control unit.
Set the time on the clock.
Right cylinder head
Withdrawal
Set the piston of the first cylinder to TDC on the compression stroke.
Make sure the engine is cold. Otherwise, let it cool down.
Turn off the ignition and remove the wire «masses» with battery.
Drain the coolant from the engine cooling system.
Remove the right front exhaust pipe.
Remove the toothed belt from the pulleys.
Remove the rear toothed belt cover.
Remove intake manifold.
Loosen the power steering pipe bracket bolt.
Mark the high-voltage wires with numbers, remove them from the spark plugs of 1-3 cylinders and move them to the side.
Loosen the clamp, remove the hose from the cooling system pipe and unscrew the bolt securing the pipe to the left cylinder head.
Loosen the bolts securing the coolant pipe flange to the rear of the cylinder head while supporting the pipe.
Pic. 3.1–87. Arrangement of a bolt of fastening of a directing pipe of the index (probe) engine oil level
Loosen the guide tube mounting bolt (probe) engine oil level on the cylinder head and pull the pipe up (pic. 3.1–87).
Disconnect from a head of the block of cylinders all electric sockets and move them aside.
Pic. 3.1–83. Arrangement of bolts of fastening of the right cover of a head of the block of cylinders
Turn out bolts and remove a cover of a head of the block of cylinders (see fig. 3.1–83).
Remove the oil deflector.
In the reverse order to tightening, gradually loosen then completely remove the cylinder head bolts (see fig. 3.1–84).
Remove the cylinder head and place it on a soft base.
Preparing the head for installation
Cm. «Preparing the left head for installation».
Installation
Installation is carried out in the reverse order of removal, taking into account the following.
Replace the cylinder head bolts.
When installing the engine, it is necessary to replace with new self-locking nuts and bolts, which were tightened by tightening to a certain angle, as well as sealing rings and gaskets.
A new cylinder head gasket must be removed from the packaging immediately before installation.
Install the gasket on the guide pins, while the inscription "oben" should point towards the head.
If work has been done on the valve train, turn the engine crankshaft two full revolutions by hand to make sure the pistons do not hit the valves.
Before installing the cylinder head, set the piston of the first cylinder and the camshaft to TDC on the compression stroke. In this case, the large holes of the fixing plates on the camshaft pulleys must be directed towards each other (see fig. 3.1–52).
Lock the crankshaft in this position by unscrewing the ignition timing sensor from the cylinder block and replacing it with set screw 3242 (see fig. 3.1–53).
Insert the cylinder head bolts and tighten by hand.
In the sequence shown in Figure 3.1–84, tighten the cylinder head bolts in two stages:
- 1st - tighten with a torque of 60 Nm;
- 2nd - tighten by an angle of 180°.
In the future, additional tightening of the cylinder head bolts is not required.
Install intake manifold.
When installing the guide tube for the pointer (probe) oil level, install the O-ring.
Install the toothed belt and adjust its tension.
Install poly V-belt.
Install the exhaust manifold.
Fill the cooling system with coolant.
Connect wire «masses» to the battery.
Turn on radio and enter the code into it.
Raise the windows with the power windows up to the stop. Then press all power window switches again for at least 1 second to the closed position to activate the power window control unit.
Set the time on the clock.
Pic. 3.1–88. Details of the left cylinder head of the six-cylinder engine: 1 - sealing ring; 2 - camshaft; 3 - bearing cover No. 1; 4 - nut, 20 Nm; 5 - bearing cover No. 2; 6 - bearing cover No. 3; 7 - bearing cover No. 4; 8 – hydraulic pusher; 9 - crackers; 10 - the upper plate of the valve spring; 11 - valve spring; 12 – oil deflector cap; 13 - valve guide sleeve; 14 - sealing ring; 15 – a head of the block of cylinders; 16 - valve
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