Warning: Engines with different codes have different automatic toothed belt tensioner pulleys.
Removing
Alignment marks
Removal of a gear belt is made on the engine which temperature should be more than 30°C. Warm up the engine if necessary.
1. Remove the auxiliary V-belt.
2. Unscrew the serpentine auxiliary drive belt tensioner.
3. Remove the top casing of a gear belt.
4. If the toothed belt is to be reinstalled, use a marker or paint to mark the direction of rotation of the toothed belt. When viewed from the front of the engine, the engine pulleys rotate clockwise.
5. Turn the engine so that the piston of the first cylinder is at top dead center.
You can turn the crankshaft of the engine in the following ways:
- Raise the front of the car and secure it on stands. Engage fifth gear and tighten the handbrake. While holding one front wheel from spinning, manually turn the other front wheel. In this case, the crankshaft of the engine will rotate;
- set the car on a flat horizontal platform, then turn on the fifth gear and manually move the car forward or backward;
- place the transmission in neutral and apply the handbrake. Using a wrench, turn the engine crankshaft at the crankshaft pulley bolt.
Warning: Do not turn the engine crankshaft by the camshaft pulley bolt, as in this case the load on the toothed belt is maximum.
6. Turn the engine crankshaft until the mark on the camshaft pulley is aligned with the TDC indicator on the cylinder head cover (see fig. Alignment marks. Check that the mark on the crankshaft pulley is aligned with the pointer on the lower timing belt housing. When the marks are aligned with the pointers, the piston of the first cylinder is at TDC on the compression stroke.
ADP engine
Alignment of the timing mark of the camshaft pulley with the pointer and the marks on the pulleys of the crankshaft and intermediate shafts on the ADP engine when the piston of the first cylinder is set to TDC
The ADP engine is equipped with an ignition distributor driven by an intermediate shaft. If the mark on the camshaft pulley is aligned with the pointer, then the marks on the crankshaft and countershaft pulleys must align.
1. While holding the crankshaft pulley from turning, unscrew the four bolts securing the pulley to the crankshaft. Remove the crankshaft pulley.
2. Unscrew screws and remove the bottom casing of a gear belt.
Engines AEB, ADP
Loosen the toothed belt tensioner bolt.
AHL engine
Loosen the toothed belt tensioner nut.
ADR engine
Toothed belt tensioner on ADR engine
- 1 - tension roller,
- 2 - hole in the piston housing,
- 3 - bolt
1. Using an 8mm Allen key, slowly turn the timing belt tensioner counterclockwise until the holes line up (2) in piston and body (see fig. Toothed belt tensioner on ADR engine). Insert a steel rod or drill shank of the appropriate diameter into the aligned hole.
Warning: The toothed belt tensioner uses the hydraulic damper principle and can only be compressed at temperatures above 30°C. Do not unscrew the bolt (3), see fig. Toothed belt tensioner on ADR engine.
2. Remove toothed belt from engine pulleys.
Warning: Do not bend the toothed belt sharply, as during operation the toothed belt may break at the point of a sharp bend, which will lead to engine damage.
Warning: After removing the toothed belt, do not change the position of the toothed belt pulleys.
Warning: If the engine crankshaft is rotated after the toothed belt has been removed, the pistons will hit the valves, causing damage to the valves and requiring extensive engine repair. Mark the position of the crankshaft pulley by marking the pulley and engine block with paint. If necessary, you can turn the engine crankshaft 90°clockwise or counterclockwise.
Warning: Check the toothed belt for wear, splitting or oiling. If there are traces of oil on the toothed belt, find the source of the oil leak and repair it before installing a new belt.
Inspection
Warning: Do not twist or kink the toothed belt.
Warning: Do not expose the toothed belt to oil, coolant or fuel.
If toothed belt teeth are chipped, the ignition distributor, water pump, oil pump, or camshaft may be stuck.
Warning: If a toothed belt breaks while the engine is running, it is possible that the pistons hit the valves, causing the valves to be bent. Check valve clearances. On bent valves, valve clearances will be much larger than required.
If there is significant wear, cracks or delamination on the outer surface of the toothed belt, check the condition of the idler treadmills.
Wear on one side of the belt indicates misalignment of the toothed belt pulleys. Check the toothed belt guide and the alignment of the toothed belt pulleys.
If there are any defects on the toothed belt, it must be replaced. Periodic replacement of the toothed belt should be carried out after 100,000 km of the car's run.
Installation
Warning: Install and tension the timing belt when the engine is cold.
1. Install the toothed belt on the crankshaft and countershaft pulleys.
Warning: When reinstalling the toothed belt, install it so that the arrow on the belt, marked before removing the belt, matches the direction of rotation of the engine pulleys. If, after installation, the toothed belt rotates in the opposite direction, cracks in the belt may occur and engine failure.
2. Reinstall and bolt the lower toothed belt guard.
3. Install the crankshaft pulley and secure it with bolts, tightening them to a torque of 25 Nm. Keep in mind that the pulley is installed in only one position.
4. Check that the camshaft and crankshaft pulley marks are aligned with the pointers.
5. Slide the toothed belt onto the camshaft pulley.
Engines AEB, ADP
Toothed belt tension elements on AEB, ADP engines
- A - holder
- B - wrench
- 1 - holder arm,
- 2 - piston,
- 3 - wrench mounted on a screw
Control dimensions for checking the correct tension of the toothed belt on AEB, ADP, ADR engines
1. Using a wrench (IN) or special key HAZET 2587 turn holder clockwise (A) tensioning roller of the toothed belt so that the piston (1) went all the way, and the piston (2) rose 1 mm above the body. While holding the toothed belt tensioner in this position, tighten the screw (3) torque 25 Nm, see fig. Toothed belt tension elements for AEB, ADP engines.
2. Turn the engine crankshaft 2 full turns clockwise and check that the marks on the crankshaft and camshaft pulleys are aligned with the pointers.
3. Check the location of the elements of the toothed belt tensioner. Dimension A must align with the top edge of the piston. Dimension D must be between 25-29 mm (see fig. Control dimensions for checking the correct tension of the toothed belt on AEB, ADP, ADR engines). In this case, the toothed belt tension is correctly adjusted.
If the top edge of the piston is within dimension B or C, it is necessary to re-adjust the toothed belt tension and check the condition of the toothed belt and idler pulley.
If the upper end of the piston is located in area B or dimension D is more than 29 mm, it is necessary to adjust the position of the toothed belt tensioner. If the upper end of the piston is located in area C, it is necessary to re-adjust the position of the toothed belt tension roller, and also check the condition of the toothed belt together with the tension roller. Install a new toothed belt and tensioner, if necessary.
ADR engine
1. Using an 8mm hex wrench, turn the timing belt tensioner counterclockwise and remove the steel rod or drill from the piston hole. Release the tension roller and remove the hex wrench. Don't turn the bolt (3), see fig. Toothed belt tensioner on ADR engine.
2. Turn the engine crankshaft 2 full turns clockwise and check that the marks on the crankshaft and camshaft pulleys are aligned with the pointers.
3. Check the location of the elements of the toothed belt tensioner. Dimension A must align with the top edge of the piston. Dimension D must be between 25-29 mm (see fig. Control dimensions for checking the correct tension of the toothed belt on AEB, ADP, ADR engines). In this case, the toothed belt tension is correctly adjusted.
If the top edge of the piston is within dimension B or C, it is necessary to re-adjust the toothed belt tension and check the condition of the toothed belt and idler pulley.
If the upper end of the piston is located in area B or dimension D is more than 29 mm, it is necessary to adjust the position of the toothed belt tensioner. If the upper end of the piston is located in area C, it is necessary to re-adjust the position of the toothed belt tension roller, and also check the condition of the toothed belt together with the tension roller. Install a new toothed belt and tensioner, if necessary.
AHL engine
Using a wrench to rotate the timing belt tensioner on the eccentric on an AHL engine
- 1 - installation mark,
- 2 - pointer
1. AHL engine. Using a wrench or a special HAZET wrench, turn the toothed belt tensioner on the eccentric five times in both directions from stop to stop, see fig. Using a wrench to rotate the timing belt tensioner on the eccentric on an AHL engine.
2. With a wrench, turn the tension roller counterclockwise until it stops, while the tension of the toothed belt will be maximum.
3. After releasing the wrench, loosen the toothed belt tension and check that the pointer is aligned with the alignment mark (see fig. Using a wrench to rotate the timing belt tensioner on the eccentric on an AHL engine). In this position, tighten the tensioner roller nut to 20 Nm.
4. At the crankshaft pulley bolt, turn the engine crankshaft clockwise two full turns and check that all alignment marks are aligned with the pointers. Check that the alignment mark of the toothed belt tensioner is aligned with the pointer.
All engines
1. Turn the engine crankshaft two full turns clockwise and check that all alignment marks are aligned with the pointers. Otherwise remove a gear belt and make its repeated installation.
2. Establish the top casing of a gear belt.
3. Tighten the V-ribbed belt tensioner to 25 Nm.
4. Install poly V-belt.
ADP engine
1. Using special Volkswagen equipment, determine the malfunctions recorded in the memory and erase the contents of the memory.
2. Check the ignition timing setting.
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