To perform the work you will need a timing belt tensioner key.
Sequence of execution
1. Prepare the car for work (see "Preparing the car for maintenance and repair").
2. Key by 10 mm we unscrew the three bolts securing the front timing belt cover.
3. Lift the cover vertically upwards, then remove it from the engine.
4. Rotate the crankshaft and visually inspect the condition of the belt.
Note: The crankshaft can be turned with a 17 mm open-end wrench (on some cars by 19 mm) by the bolt that secures its pulley or by the teeth of the flywheel with a large slotted screwdriver. To do this, remove the rubber plug from the hole in the clutch housing (see "Timing Belt - Replacement").
The belt must be clean - no dirt or oil on its surface. A belt with tears, cracks, delamination, cut or worn teeth, abrasions down to the cord must be replaced (see below, "Timing Belt - Replacement").
5. Using two fingers, try to turn the belt 90° in the area between the crankshaft and camshaft pulleys, applying a force of 15-20 N·m (1.5-2.0 kgf·m) to it.
(The article is taken from an online resource: VAZbook.ru)
If the force applied is not enough to turn the belt to the required angle, then the belt is overtightened; if the belt can be turned to a greater angle, it is not tensioned enough.
Warning! Adjust the belt tension on a cold engine. Excessive belt tension, oil and dirt on the belt will shorten the service life of the belt, as well as the bearings of the tension roller and the coolant pump. If the belt tension is too low, it may jump over several teeth of the camshaft pulley.
6. To check the relative position of the camshaft and crankshaft, set the piston of the first cylinder to TDC of the compression stroke. To do this:
a. Remove the rubber plug installed in the upper part of the clutch housing.
b. Through the resulting window, using a slotted screwdriver with a wide blade, turn the crankshaft by the teeth of the flywheel ring...
...until the mark on the camshaft pulley and the protrusion on the rear timing belt cover are aligned.
In this case, the mark on the flywheel should be aligned with the center of the scale.
Recommendations: If the relative position of the crankshaft and camshaft is disturbed, turn the crankshaft until the mark aligns with the scale center. Loosen the belt tension and remove it from the camshaft pulley. Turn the camshaft until the mark on its pulley aligns with the protrusion on the rear cover. Without changing the relative position of the shafts, put the belt on the camshaft pulley and adjust the belt tension.
7. Key by 17 mm loosen the tension roller mounting nut.
8. Turning the roller with a special key, we adjust the belt tension and, holding the roller in this position, tighten the nut that secures it.
9. Check the belt tension (see above) and, if necessary, repeat the adjustment.
10. Finally tighten the roller mounting nut to a torque of 33.2-41.2 N·m (3.4-4.2 kgf·m).
11. Install the front belt cover in place and tighten the bolts that secure it.