A burnt or defective cylinder head gasket is determined by the following signs:
- Reducing engine power.
- Reducing the coolant level. In this case, white steam comes out of the exhaust pipe.
- Reducing the level of engine oil.
- The presence of coolant in the engine oil. This will increase the oil level. If there is coolant in the engine oil, the engine oil turns gray and has foam bubbles.
- The presence of engine oil in the coolant.
- Intensive release of bubbles from the coolant.
- Reducing compression in two adjacent engine cylinders.
Withdrawal
Turn off the ignition and remove the wire «masses» from the battery.
Attention
- When the wires are disconnected from the battery terminals, the data on the recorded malfunctions are erased in the memory blocks of the control devices, therefore, before disconnecting the wires, it is necessary to contact the workshop to recall the malfunctions recorded in it. After connecting the wires to the battery terminals, it is necessary to activate and reprogram the power windows, as well as the position of the rear-view mirrors and seats.
- If the car has a radio with a code, then before disconnecting the wires from the terminals from the battery, check that there is a code to reactivate the receiver. Otherwise, it will be possible to put the radio receiver into operation only at a specialized station.
Remove the air filter cover. Loosen the clamp and disconnect the air tube.
Unscrew the screws and remove the engine cover.
Disconnect the crankcase ventilation hose 2 from the cylinder head cover (pic. 2.15) and turn it aside.
Supercharged engine. Disconnect pipe 1 (pic. 2.15) pressurization from the combination valve in the cylinder head cover. Unscrew and remove the heat shield 3.
Drain the coolant from the engine cooling system.
Unscrew the expansion tank from the bracket and move it to the side along with the hoses connected to it.
Set the front panel of the body to the service position.
Clean the spark plugs using a brush, vacuum cleaner or compressed air to prevent dirt from entering the engine cylinders after the spark plugs are removed. Unscrew the spark plugs.
Remove the fuel line mounting bolts and remove the low pressure hose from the pressure regulator (see fig. 2.16). Do not open the fuel system.
Security note. The fuel system is under pressure. Depressurize the fuel system before disconnecting the fuel lines. To do this, cover the connection point with a rag and, being careful, disconnect. When disconnecting system components, fuel can splatter, so use goggles to protect your eyes from fuel getting into them.
Remove the fuel line with injectors from the intake manifold and place it on a clean rag at the rear of the engine compartment.
Disconnect low pressure hose 1 (pic. 2.17) from the fuel vapor recovery valve (activated carbon containers).
Loosen the clamps and remove the cooling system hoses (see fig. 2.17).
Unlock holder 2 (pic. 2.17) suction pipe of the water pump and remove it together with the hoses.
Remove the top cooling pipe from the rear of the cylinder head.
Loosen the clamp and disconnect the air pipe from the throttle assembly.
Disconnect the accelerator cable from the throttle assembly.
Engine 150 hp Unscrew bolts 1 and 2 (pic. 2.18) fastenings of an oil pipeline and bolts 3 fastenings of a turbocompressor.
Engine 150 hp Unscrew the support strut located between the cylinder head and the intake pipe near the generator.
Engine 125 hpUnscrew the lower suction pipe mounting from the rubber-metal supports (see fig. 2.19). Also, disconnect the electrical connectors and the low pressure hose from the inlet length switch valve.
Remove the dipstick to measure the oil level.
Unscrew the bolts and remove the suction pipe from the cylinder head (see fig. 2.20).
Mark electric sockets and disconnect them from a head of the block of cylinders.
Disconnect the upper and lower hoses from the radiator. To do this, remove the fixing brackets on the side of the coupling, then disconnect the hoses.
Release the spring clip and remove the lambda sensor electrical connector from the holder and disconnect it.
Unscrew the front exhaust pipe with catalytic converter from the exhaust manifold.
Remove the upper casing of the toothed belt and set the piston of the first cylinder to TDC.
Loosen the toothed belt tension and remove it from the camshaft pulley.
Unscrew the nuts securing the cylinder head cover and remove it together with the seal (see fig. 2.21).
In the sequence from 1 to 10, shown in Figure 2.22, unscrew the cylinder head mounting bolts. An 8mm hex wrench must be used to loosen the bolts.
Check that all pipes, hoses and electrical connectors are disconnected from the cylinder head.
Remove the cylinder head from the engine and place it on two pieces of wood.
Remove the cylinder head gasket.
Installation
Before installing a new cylinder head, remove the plastic plugs designed to protect the open cylinder head valves.
The mating surfaces of the head and cylinder block must be 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. Clean channels if necessary.
Clean the bolt holes in the cylinder block. Screwing a bolt into an oil-filled hole can rupture the block due to hydraulic pressure.
With a metal ruler and feeler gauge, check the flatness of the mating surfaces (see fig. 2.23). The deviation from flatness should be no more than 0.1 mm.
If there are small defects on the mating surface of the cylinder head, they can be removed by machining.
Cylinder head height after machining must be 139.25 mm (see fig. 2.24).
A cylinder head that has cracks between the valve seats or the valve seat ring and the first thread of the spark plug can be installed without reducing their service life. It is necessary to repair the head if the crack width exceeds 0.5 mm.
Check that guide bushings are installed in the cylinder block to center the gasket and the cylinder head (see fig. 2.25). If there are no bushings, install them.
When installing the cylinder head, a new cylinder head gasket must be used.
Remove the cylinder head gasket from its sealed package just before installing it on the cylinder block.
Check that the new cylinder head gasket is the same type as the original and that the TOP or OBEN·markings are facing up. Position the new cylinder head gasket on the surface of the cylinder block on the guide pins. Check that the holes are correctly aligned with the channels of the cooling and lubrication system.
On a 125 hp engine.Before installing the cylinder head, turn the timing belt tensioner lever to its original position.
Check that the crankshaft and camshaft are set to the position where the piston of the first cylinder is at TDC. Set them to this position if necessary.
Being careful, with the assistant establish a head on the block of cylinders.
At installation it is necessary to use new bolts of fastening of a head of the block of cylinders.
Insert and hand tighten the cylinder head bolts.
Engine 150 hp Loosen bolts 1 and 2 two turns (pic. 2.26) fastenings of a support of a turbocharger to exclude possible distortions at installation of a head of the block of cylinders.
Gradually, in the sequence shown in Fig. 2.27 tighten bolts of fastening of a head of the block of cylinders in several stages.
Tightening torques for the cylinder head bolts.
AJP/AWT engine:
1st stage - tighten with a torque of 40 Nm;
2nd stage - tighten by an angle of 90°;
Step 3 - Tighten 90°
Engine AEB/ANB/APU/ADR:
1st stage - tighten with a torque of 60 Nm;
2nd stage - tighten by an angle of 90°;
Step 3 - Tighten 90°
Attention. Do not tighten the cylinder head bolts when the engine is warm. When installing a new cylinder head with a camshaft, after installing the cylinder head, lubricate the mating surfaces of the hydraulic tappets and camshaft cams with a thin layer of grease.
Before installing the inner gasket of the cylinder head cover, lubricate the transitions (even on the opposite side) from bearing caps to cylinder head with Loctite Ultra Black or AUDI D 454 300 A2 (see fig. 2.28). Install the cylinder head cover gasket.
Install the cylinder head cover and gradually, crosswise tighten the cover nuts to a torque of 10 Nm.
Engine 150 hpScrew the turbocharger support to the cylinder block and turbocharger. Bolt tightening torques on AWT motor 25 Nm and on AEB/ANB/APU motor 40 Nm.
Install the toothed belt on the camshaft pulley and adjust its tension.
Install V-belts and V-ribbed belts and adjust their tension.
Screw the catalytic converter to the exhaust manifold.
Connect the electrical connector of the lambda sensor, install it in the holder and secure with a spring clip.
Screw the suction pipe with new gaskets to the head and fix it with bolts, tightening them gradually crosswise with a torque of 10 Nm.
Engine 125 hpFix the lower part of the suction pipe in rubber-metal supports.
Engine 150 hpScrew the support stand between the cylinder head and the suction pipe and tighten the mounting bolts to 20 Nm.
Install the fuel line with injectors on the suction pipe and secure with bolts, tightening them with a torque of 10 Nm.
Install and secure holder 2 (pic. 2.17) suction pipe of the water pump.
Install spark plugs and ignition coils.
Reinstall and secure the wires from the suction pipe and the Hall sensor.
Screw the upper pipe of the cooling system to the rear of the cylinder head and the suction pipe and tighten the bolts to a torque of 10 Nm.
Install the expansion tank in the holder.
Engine 150 hpInstall the oil line and bolt to the cylinder head, tightening to 20 Nm. Install the turbocharger with a new gasket on the exhaust manifold and secure with bolts, tightening them to 35 Nm.
Install the accelerator cable.
Connect the upper and lower hoses to the radiator.
Check that all hoses, pipes and electrical connectors are connected as previously marked.
Reinsert the dipstick to measure the oil level.
Check the engine oil level and top up if necessary. If a new cylinder head is installed, the engine oil and oil filter must be changed.
Fill the cooling system with fresh coolant.
Supercharged engine. Connect pipe 1 (pic. 2.15) booster to the combination valve and bolt it to the cylinder head cover by tightening the bolts to 10 Nm. Install and screw on the heat shield by tightening the fastening bolts to 5 Nm.
Screw the crankcase ventilation pipe to the cylinder head cover by tightening the fastening bolts to a torque of 10 Nm.
Reinstall the air tube and air filter cover.
Connect wire «masses» to the battery. Repeat the operations for memorizing the position of seats, mirrors, etc., as well as set the time on the clock and enter the code into the radio.
Start the engine and warm it up to operating temperature. Stop the engine and check the engine oil and coolant levels and all connections for leaks.
Attention. When disconnecting the various electrical connectors, errors are stored in the memory, which must be canceled after installation.
Visitor comments