We replace the valve stem seals when repairing the cylinder head, as well as when the caps are worn.
A sign of wear on valve stem seals is increased oil consumption, as well as the presence of blue smoke from the exhaust pipe after starting the engine and when braking the engine after a long drive under load.
An indirect sign is also the oiling of the electrodes of the spark plugs.
To do the job, you need the tools that are needed to remove the cylinder head cover, a 12 wrench, tweezers or a magnetized screwdriver and also:
Valve spring compressor
Pliers for oil scraper valves
Or you can use an inertial oil seal remover.
Preparing the car for work. Disconnect the negative battery terminal.
On K7J K7M engine
Unscrew all the spark plugs
Remove the cylinder head cover (article - Replacing the cylinder head cover gasket Renault Sandero)
Set the piston of the first cylinder to the TDC position of the compression stroke (described in the article - How to set the TDC of a Renault Sandero engine)
In this position, you can crack the valves of the first and fourth cylinders, you can safely drop the valves into the cylinder
To set the piston of the 1st cylinder to the TDC position of the compression stroke, the removal of the top cover of the timing belt is required (to gain access to the alignment marks on the camshaft pulley and on the head of the block), which entails laborious preliminary operations to remove the right suspension mounts of the power unit.
With an accuracy sufficient to set the pistons of the 1st and 4th cylinders to the TDC position when replacing the valve stem seals, the camshaft can be set to the desired position, controlling it visually.
When turning the crankshaft, the camshaft must be installed so that the heels of the rocker arms of the drive of both valves of the 1st or 4th cylinder rest on the back of the camshaft cams, and the rocker arms can be moved by rocking within the gap.
Weaken evenly the tightening of the five bolts securing the axis of the rocker arms of the valve drive
Remove the bolts from the head holes
The bolts differ in the shape of their heads, you need to remember their position and install them in their places
Remove the axle assembly with rocker arms
If we do not replace the rocker arms or the camshaft, then it is not necessary to remove the rocker arms from the axle in order to install them in their places during assembly.
This way the valve clearances will not differ much.
We install a device for compressing valve springs by screwing a bolt securing the axis of the rocker arms into one of the holes in the head of the block and hooking the device on this bolt.
We compress the valve spring and remove two crackers from the spring plate using tweezers or a magnet.
Remove the fixture.
Remove the spring plate
Remove the valve spring
The support washer can be left in place
Compress the valve stem seal from the valve guide.
To do this, install the inertial puller on the cap and sharply strike the striker on the sleeve of the puller collet.
Then we sharply hit the handle of the fixture with the striker, thereby compressing the cap from the sleeve.
If there is no inertial cap remover, remove the cap with a special tong-type remover or pliers, applying force straight up and without turning the cap so as not to damage the valve guide.
The valve guide is made of sintered metal, the lip breaks easily, so be careful not to damage it.
It is recommended to remove the springs from them before installing the valve stem seals, if there are no plastic mounting bushings in the kit.
Lubricate the inner surface of the caps with engine oil and move the cap along the valve stem to the guide sleeve
We install the mandrel for pressing the cap and with light blows on the mandrel we press the cap until it stops (you can choose a mandrel of a suitable diameter).
Install the spring and valve disc in reverse order.
We install crackers with the help of a device so that they fit into the grooves of the valve stem.
After installing the crackers, we hit the end of the valve with a hammer through the metal rod so that the crackers sit in place.
We also replace the valve stem seals of the second valve of the first cylinder and two valves of the fourth cylinder
We turn the crankshaft half a turn so that the pistons of the second and third cylinders are at TDC, and replace the valve stem seals of the remaining valves.
Reinstall the rocker axle with rocker arms and check the valve clearances.
Install all removed parts in reverse order.
We replace K4M valve stem seals in the same way.
The difference is in the way the piston of the first cylinder is set to the TDC of the compression stroke.
And the K4M engine has two camshafts and no rocker shaft. Removal of camshafts will be required.