It must be borne in mind that failure of the timing belt (open or cut teeth) can lead to sticking of the valves into the pistons due to a mismatch in the angles of rotation of the crankshaft and camshafts and, as a result, to expensive engine repair.
The surface of the gear part of the belt should not have folds, cracks, undercuts of teeth and delamination of the fabric from rubber. The reverse side of the belt must be free of wear, exposing the cord, and no signs of burning.
On the end surfaces of the belt there should be no delamination and disintegration. If damaged, the belt must be replaced. The belt must also be replaced if there is any trace of oil on it (before replacing the belt, the cause of oiling should be eliminated) or when the failed tensioner and the belt support roller, coolant pump are replaced.
Most of the operations for checking the condition and replacing the timing belt for clarity are shown on a dismantled engine.
To perform operations in the engine compartment, remove the air filter.
Next, you can begin to check the condition of the timing belt. For this…
We turn on the fifth gear in the gearbox and hang out the right front wheel. Turning the wheel clockwise, rotate the crankshaft and check the condition of the timing belt.
If the moving pointer is offset from the fixed:
- counterclockwise - the belt tension is insufficient;
- clockwise - the belt will be pulled.
In both cases, adjust the belt tension (see below) or replace the belt with a new one.
To replace the belt, remove the right front wheel and securely fix the car on a factory-made stand.
Remove the drive belt of auxiliary units.
We turn off a bolt of fastening of a pulley of a drive of auxiliary units. To keep the crankshaft from turning, the assistant must engage fifth gear and depress the brake pedal.
Once again we check the coincidence of the alignment marks on the camshaft pulleys.
Next, we have to remove the bracket of the right support of the power unit, as the timing belt is worn on it.
To remove the belt from the pulleys, you need to reduce its tension. To do this, turn the coolant pump housing counterclockwise in the cylinder block socket while loosening the pump mounting screws.
Attention! To avoid leakage of coolant through the pump O-ring, we only tighten the screws until the pump body can be turned using a tool.
You can turn the pump with an open end wrench “41” for the hexagon made on its body.
Before installing a new belt, check the condition of the coolant pump, tensioner pulley and belt support pulley.
When rocking and rotating the pump pulley and rollers by hand, there should be no play, jamming, or noise in the bearings. In the presence of the indicated malfunctions, replace the pump with a new one.
To replace the tensioner with the roller assembly, remove the cylinder block bracket, to which the bracket of the right support of the power unit is attached.
We install the tensioner and the support roller of the belt in the reverse order. Tighten the tensioner mounting bolts with a torque of 25 N · m, and tighten the support roller bolt with a torque of 50 N · m.
Before installing the belt, make sure that the alignment marks on the camshaft pulleys and the marks on the crankshaft pulley are aligned with a slot on the timing case back cover. In this position, we put the belt on the crankshaft pulley. Pulling both branches of the belt, we start the front branch by the support roller, and the rear, putting it on the pulley of the coolant pump, by the tensioner pulley. We put the belt on the camshaft pulleys, eliminating the sagging branches of the belt.
We tighten the belt by turning the coolant pump clockwise until the combination of the movable and fixed indicators of the tensioner (see above). In this position, tighten the pump mounting screws.
We check the belt tension and the alignment of the alignment marks of the crankshaft and camshafts. If the installation marks do not match, repeat the operation to set the valve timing. Make sure there is no leakage from under the coolant pump. Otherwise we replace a sealing ring of the pump case.
If the gas distribution phases are set correctly and the belt tension is normal, then we install the lower front cover of the timing belt and the auxiliary drive pulley. We tighten the bolt of fastening of the pulley of the drive of auxiliary units at the moment to 95 Nm. Then we turn it 30 °, and then another 15 °.