Check the quality and tension of the engine timing belt every time the engine is serviced.
A loose belt wears out the teeth of the belt quickly and can cause the belt to jump over the toothed pulleys, resulting in camshaft misalignment and potentially causing catastrophic engine damage.
In the absence of special testers, the belt tension can be checked according to the “rule of thumb”, and the deflection can be determined using a ruler.
According to this rule, the deflection between the centers of the pulleys is from 180 to 280 mm, the deflection should be approximately 6 mm.
You can also check the approximate tension by twisting the leading branch of the belt along the axis.
If you manage to twist the branch more than 90˚ with your hand, the belt is loose.
When inspecting the belt, you need to pay attention so that there are no cracks, cuts, delaminations.
The surface of the belt must be free of oil.
Preparing the car for the task. We install it on a lift or a viewing ditch.
Remove the right support of the power unit for this:
We substitute a jack under the oil pan through a wooden or rubber block.
We remove the fuel pipes from the holders located on the support bracket
Remove the wire harness holder from the support bracket hole
With a 16 head, unscrew the three bolts securing the support bracket to the top cover of the timing drive
We unscrew the three bolts securing the support to the body
Removing the right support
Removing the right mudguard (article - Removing protection Renault Sandero power unit)
Checking and replacing the belt on the K4M 1.6L engine
The location and installation of the belt is shown in Figure 6.
With a 13 head, unscrew the three bolts and two nuts securing the upper timing cover
Remove the top cover
With a head of 18, turn the crankshaft clockwise and inspect the timing belt
At normal belt tension, pointer 1 should align with the notch of pointer 2 of the tensioner
If the movable pointer is offset relative to the fixed pointer, then tighten the belt.
We loosen the tightening of the tension roller fastening nut with a 13 wrench and turn the roller clockwise with a hexagon by 6, pulling the belt until the pointers align.
While holding in this position, tighten the roller nut.
To replace the belt, remove the auxiliary drive belt (Replacing the accessory belt Renault Sandero)
Remove the top timing cover
We turn on the fifth gear and the assistant presses the brake pedal
With a head of 18, we unscrew the bolt securing the accessory drive pulley
Removing the bolt with washer
Remove the accessory drive pulley
With a head of 8, unscrew the four bolts securing the lower timing cover
Remove the cover
Set the crankshaft and camshafts to the top dead center of the first cylinder.
To do this, unscrew all the candles.
We screw the bolt of the accessory drive pulley into place by installing a set of suitable washers.
To determine the position of the camshafts, it is necessary to remove the plugs from the holes in the left end of the cylinder head.
Remove the air intake with a resonator
In the center of the plug, pierce a hole with a screwdriver
Remove the plug from the hole in the cylinder block. Also extract another stub
We turn the crankshaft clockwise, the grooves on the ends of the camshafts should take a horizontal position, and are shifted down relative to the axes of the camshafts fishing.
To fix the camshafts in this position, a device can be made from a metal plate five millimeters thick.
The dimensions of the fixture are shown in the figure
Install the device in the grooves of the shafts
We check that the crankshaft is in the TDC position of the pistons of the 1st and 4th cylinders. For this:
Unscrew the plug with the E14 head
Insert the installation pin into the hole (shown with the pallet removed)
When the crankshaft is in the TDC position of the pistons of the 1st and 4th cylinders, the mounting pin 1 must be screwed into the hole to the end of the thread and abut against the milled area 2 on the crankshaft web.
After that, the crankshaft will be impossible to turn.
If, when screwing in the adjusting pin, it rests, and the end of the adjusting nut on the pin does not come into contact with the end face of the boss of the hole in the cylinder block (there will be a gap between the nut and the boss), then you need to turn a little (by removing the device from the grooves of the camshafts) crankshaft shaft counterclockwise.
Then you need to screw the mounting pin into the hole of the cylinder block to the end (until the ends of the pin nut and the boss of the hole in the block touch) and turn the crankshaft clockwise until the platform of the shaft cheek stops against the pin.
Install the camshaft locking tool, if it was removed.
An M10 bolt can be used as a mounting pin
We screw two adjusting nuts onto the bolt and lock them so that the length of the threaded part of the bolt is 75 mm.
Turn the roller counterclockwise, reducing the tension of the timing drive
Remove the belt from the tensioner
Remove the belt from the coolant pump pulleys, crankshaft and camshafts
Belt marking (number of teeth 131, width 25.4 mm)
When replacing the belt, it is advisable to replace the tension and support roller, for this we unscrew the tension roller fastening nut
Remove the tension roller from the coolant pump housing stud
Use the TORX T50 key to unscrew the screw securing the support roller
Remove the support roller and its bushing.
Installing the timing belt
We orient the belt so that the arrows on the belt coincide with the direction of movement of the belt clockwise.
We install the belt on the gear pulleys of the crankshaft, coolant pump, camshaft pulleys.
Then, at the same time, we put the belt on the tension roller and install the roller on the stud of the coolant pump housing.
When installing the tension roller, insert the bent end 1 of the roller bracket into the recess 2 of the coolant pump housing.
Adjust the belt tension as described above.
We unscrew the locking pin from the hole in the cylinder block and remove the device for fixing the camshafts.
Rotate the crankshaft two turns clockwise until the grooves on the camshafts take the position corresponding to the top dead center of the 1st piston.
We twist the plug into the hole in the cylinder block.
With light blows of a hammer with a plastic striker, we press new plugs into the holes of the cylinder head.
Assemble the parts in reverse order.
We replace the bolt securing the auxiliary drive pulley with a new one and tighten it with a torque of 40 Nm, then tighten it by 110˚.
We tighten the bolt for fastening the bracket for the tension roller of the auxiliary drive belt with a torque of 21 Nm.
We tighten the bolt for fastening the timing belt support roller with a torque of 50 Nm.
Tighten the nut of the timing belt tension roller with a torque of 28 Nm.
We tighten the M8 bolt for fastening the upper timing cover with a torque of 22 Nm.
We tighten the M10 bolt for fastening the upper timing cover with a torque of 44 Nm.
We tighten the bolt for fastening the lower timing cover with a torque of 8 Nm.
Replacing the timing belt on the K7J and K7M engines
We set the piston of the first cylinder to the TDC of the compression stroke and remove the auxiliary drive pulley and the lower cover of the timing belt, as described in the article - Checking and replacing the Renault Sandero auxiliary drive belt
We remember or mark in any way the position of the tension roller relative to the axis, loosen the tightening of the roller fastening nut
Turn the roller clockwise, thereby loosening the tension of the timing belt
Remove the belt from the toothed pulley of the water pump
Remove the belt from the camshaft
Remove the belt from the crankshaft and tensioner
And remove the belt completely
The original belt must be marked with arrows indicating the direction of its movement when the engine is running.
If there are no such arrows on the belt, then you need to apply them with paint or a felt-tip pen to set the belt in its original position.
To replace the tension roller, finally unscrew the nut from its axis
Shooting a video
Install the new tension roller in reverse order. In this case, the holes for a special key should be directed outward.
Installing the belt
We install the belt first on the camshaft pulley, orienting it with the arrows "B" in the direction of movement when the engine is running and aligning the risk "A" with the alignment mark on the pulley.
Then we pull the leading branch onto the water pump pulley
And the crankshaft pulley, also aligning the notch on the belt with the alignment mark on the pulley.
After that, install the belt on the tension roller.
We tighten the belt by turning the tension roller counterclockwise until the marks made earlier coincide, and tighten the roller fastening nut.
We install the accessory drive pulley on the crankshaft and turn the crankshaft by two turns for the fastening bolt and check that the marks are set correctly.
After that, we assemble all the parts in the reverse order.