It is not necessary to perform a computer diagnostics of the car engine to know that it is necessary to change the spark plugs. Information on the frequency of this procedure can be taken from the service book. The mileage on one set of spark plugs is 30,000 km. And you don’t have to think for a long time to use the surrender service scrap heavy equipment.
Iridium candles are able to operate without problems for 50-100 thousand km. If we are talking about Russian cars that drive on fuel of lower quality, replace the candles more often.
To begin with, detach the cap of the high-voltage wire from the insulator of the plug in an upward motion and remove it to the side. In some cases it will require a lot of force to remove.
Some foreign cars have a multi-valve engine, use a spark plug wrench (hexagonal end) to unscrew the spark plugs. You can put a screwdriver in the hole of the wrench tube and use it as a lever. Rotate counterclockwise and remove the spark plug from the engine head. Inspect it carefully. The light brown color of the surface indicates proper operation of the spark plug.
See if there is oil on the threads and soot on the body. If these signs are found, replace the spark plug. The model of the new spark plug is worth looking up in the car’s instruction manual before buying.
Spark plugs are capricious to the quality of fuel used, so choose carefully what you fill up with.
Before installing the spark plug, study the instruction manual. The distance between the electrodes is prescribed there. By changing the shape of the side electrode (bending or straightening), adjust the size of this gap. After adjusting it put the plug in place, screwing in first by hand, then with a spark plug wrench (all the way into the head of the block). Do not grease the thread for easy screwing in. Connect the cap of the high voltage wire to the insulator of the plug.
If you will put back the old candle, which passed the visual inspection, it can be previously cleaned of dirt and carbon deposits. The main thing is not to use metal brushes, they will damage the surface.
Rules for installing the spark plug
Make sure that:
Dirt near the spark plug hole does not get into the combustion chamber itself;
place the part with the correct tightening torque. It will break if the tightening torque is too high, and too low a torque will compromise the heat sink and sealing quality.
The tightening torque depends on the type of spark plug. Tighten new plugs equipped with a gasket ring to 90 degrees. Used plugs tighten to 30 degrees, as the o-ring has become narrower during use.