Replacing spark plugs in gasoline engines (Skoda Yeti 5L)

Caution: Spark plugs should only be replaced when the engine is cold or slightly warm. Removing spark plugs on a hot engine can damage the threads in the cylinder head.

1. Spark plug installation details are given in Section 7 Chapter 5. The types of spark plugs used and their interelectrode gaps are indicated in Specifications for Chapter 5.

2. To remove the spark plugs on a 1.2L engine, mark the high-voltage wires and disconnect them from the spark plugs using the T10112A tool.

3. On other engines, the ignition module and high-voltage wires are not used; instead, an ignition coil is installed directly on each coil. Therefore, to remove the spark plug, you must remove the ignition coil from it (see Section 7 Chapter 5). If the coil does not need to be removed, its connector can be left in place, but the coil wiring should first be released from the holders so that it is not stretched.

4. To remove the spark plugs, use a special long spark plug wrench, for example No. 3122B.

5. Assess the condition of the spark plugs (see illustrated insert). If necessary, correct any possible problems that can be judged by the condition of the spark plugs. Carbon deposits on the electrodes can be removed with compressed air under pressure, do not use a wire brush for this purpose. Checking and adjusting the interelectrode gap between spark plug replacements is not required.

6. When installing new spark plugs and the old ignition coils/old high-tension cables remain, apply a bead of sealant G 052 141 A2 with a diameter of 1-2 mm to the ignition coil/high-tension cable connector on the spark plug side (see illustration).

Note: New ignition coils/high voltage wires come with the spark plug connector already lubricated. This grease prevents the connector seal from sticking to the spark plug.

7. Installation is carried out in reverse order. Tighten spark plugs to specifications; connect the wiring in the same places and lay the wiring as it was done before removal.





Symptoms: The presence of soot indicates an over-rich fuel-air mixture or weak spark intensity. Causes misfires, difficult starting and leads to unstable engine operation.

Recommendations: Check if the air cleaner is clogged. Try using spark plugs with a longer insulator, which increases resistance to fouling.



Symptoms: Oiling of the spark plug is caused by wear of the oil deflector caps. Oil enters the combustion chamber through worn valve guides or piston rings. Causes misfires, difficult starting and leads to unstable engine operation.

Recommendations: Perform mechanical repairs and replace spark plugs.



Symptoms: Porous, white insulator, eroded electrodes and no deposits. Leads to a reduction in spark plug life.



Recommendations: Check if it meets the requirements Specifications the glow plug rating, whether the ignition timing is set correctly, whether the fuel-air mixture is too lean, whether there are any vacuum leaks in the intake manifold, and whether the valves are stuck. Also check the coolant level and whether the radiator is clogged.



Symptoms: Electrodes are melted. The insulator is white in color, but can also be contaminated due to misfires or foreign particles entering the combustion chambers. May cause engine failure.

Recommendations: Check the glow number of the installed spark plugs, the ignition timing, and the quality of the mixture (isn't it too poor?), whether the cooling system is clogged and whether the lubrication system is functioning normally.





Symptoms: The insulator has a yellowish color and a polished appearance. Indicates a sudden increase in temperature in the combustion chambers during sudden acceleration. Normal deposits are melted, taking on the appearance of a varnish coating. Causes misfires at high speeds.

[Material is available on the website www.SKODABOOK.ru]

Recommendations: Change the spark plugs (cooler, while maintaining the same driving style).



Symptoms: Combustion waste products enter the interelectrode space. Solid deposits accumulate, forming a bridge between the electrodes. Causes ignition failure in the cylinder.

Recommendations: Remove deposits from the interelectrode space.





Symptoms: Gray-brown color and slight wear of the electrodes. The glow number of the spark plugs corresponds to the engine type and its general condition.

Recommendations: When replacing spark plugs, install spark plugs of the same type.



Symptoms: Soft, brownish deposits on one or both spark plug electrodes. The source of their formation is the additives used in oil and/or fuel. Excessive build-up can cause electrode insulation and cause misfires and rough engine operation under acceleration.

Recommendations: If deposits accumulate quickly, replace the oil seals to prevent oil from entering the combustion chambers. Try changing the brand of fuel.



Symptoms: Rounding of the electrodes with a small accumulation of deposits at the working end. The color is normal. Leads to difficulty starting the engine in cold, damp weather and increased fuel consumption.



Recommendations: Replace the spark plugs with new ones of the same type.



Symptoms: Insulators may be chipped or cracked. Inaccurate spark plug gap adjustment techniques can also lead to damage to the insulator. May cause damage to pistons.



Symptoms: After misfiring for an extended period of time, deposits may become loose while the combustion chamber remains at operating temperature. At high speeds, deposits flake off from the piston and stick to the hot insulator, causing misfires.

Recommendations: Replace the spark plugs or clean and reinstall the old ones.





Symptoms: Can be caused by foreign material entering the combustion chamber or by the piston hitting a spark plug that is too long. Lead to failure of the cylinder and damage to the piston.

Recommendations: Remove foreign particles from the engine and/or replace the spark plugs.