3.25. Replacement of spark plugs

In electronic system of ignition, very high voltage is generated! Be attentive, observe all necessary precautionary measures at service of any components of system, including not only the main (the ignition module, the coil and VV of a wire), but also and accompanying, such as candle sockets, tachometer and other equipment. Persons with the implanted pacemaker of ignition should not be allowed to service of components of system!

Efficiency of return of the engine considerably is defined by correctness of functioning of spark plugs. It is important that candles of the corresponding type were installed on the engine (see Settings and routine maintenance of the car). Need for unplanned service of spark plugs arises extremely seldom provided that actually the engine is in good repair. In order to avoid casual damage of electrodes, it is not necessary to make cleaning of candles without use of the special equipment.

In most cases replacement of spark plugs requires existence of a special candle head (with an elastic insert inside) complete with the ratchet drive, and also set for a safe detachment of tips of VV of wires from shafts of spark plugs the special tool is also issued though its application and is not strictly obligatory. Use of a dynamometer key will allow to achieve the correct effort of tightening of candles.

Tools necessary at replacement of spark plugs

1 — the Candle head - Is equipped with the special elastic insert excluding a possibility of casual damage of the porcelain insulator at a candle reversing.
2 — the Dynamometer key - without being among obligatory tools, provides a reliable guarantee of correctness of effort of tightening of spark plugs.
3 — the Ratchet drive - Is used in a set with a candle head and a dynamometer key.
4 — the Extender - Depending on model and a complete set access to spark plugs can be limited by its auxiliary units in various degree therefore use of extenders of the corresponding form and design will allow to facilitate implementation of the procedure considerably.
5 — the Tool for measurement and correction of interelectrode gaps of spark plugs - Is issued several types of this sort of tools - make sure that the tool is completed with the probe corresponding by the size to gaps of candles of your car.

Coal deposits
Symptoms: Availability of soot indicates reenrichment of fuel-air mix or weak intensity of a spark. Causes admissions of ignition, complicates start and results in instability of operation of the engine.
Recommendations: Whether check the air cleaner is hammered whether fuel level in the float-operated camera is not too high, whether the air gate is jammed and whether contacts are not too worn-out. Try to use candles with longer insulator that increases the resilience to pollution.

Symptoms: Oiling of a candle is caused by wear of maslootrazhatelny caps. Oil gets to the combustion chamber through worn-out guides of valves or piston rings. Causes admissions of ignition, complicates start and results in instability of operation of the engine.
Recommendations: Perform mechanical recovery work and replace candles.

Symptoms: Porous, white insulator, erosion of electrodes and lack of any deposits. Leads to reduction of service life of a candle.
Recommendations: Check whether the kalilny number of the established candles conforms to requirements of Specifications (in the Head Nastroyki and routine maintenance of the car), whether the ignition advancing corner is correctly exposed, whether too poor fuel-air mix moves, whether there is no leak of vacuum of the inlet pipeline and whether valves are jammed. Check also the level of a cooler and whether the radiator is corked.

Too early ignition
Symptoms: Electrodes are melted off. The insulator has white color, but maybe is polluted owing to admissions of ignition or hit in combustion chambers of foreign particles. Can lead to an engine exit out of operation.
Recommendations: Check kalilny number of the established candles, an ignition advancing corner, quality of mix (whether it is not too grown poor) whether the cooling system is corked and whether the lubrication system normally functions.

Electroconductive luster
Symptoms: The insulator has yellowish color and the polished appearance. Speaks about sudden temperature increase in combustion chambers at sharp acceleration. Usual deposits at the same time are melted off, taking a form of a varnish covering. Leads to admissions of ignition at high speeds of the movement.
Recommendations: Replace candles (colder, at preservation of a manner of driving).

Short circuit of electrodes
Symptoms: Waste of products of combustion gets to interelectrode space. Firm deposits accumulate, forming a crossing point between electrodes. Leads to refusal of ignition in the cylinder.
Recommendations: Remove deposits from interelectrode space.

Normal state of a candle
Symptoms: Gray-brown color and easy wear of electrodes. The Kalilny number of candles corresponds to type of the engine and its general state.
Recommendations: When replacing candles establish candles of the same type.

Symptoms: Soft deposits of brownish color on one or both electrodes of a candle. A source of their education are the applied additives to oil and/or fuel. Excessive accumulation can lead to isolation of electrodes and cause admissions of ignition and unstable operation of the engine at acceleration.
Recommendations: At bystry accumulation of deposits change maslootrazhatelny caps that will prevent hit of oil in combustion chambers. Try to replace fuel brand.

Symptoms: A rounding off of electrodes with a small congestion of deposits on the working end. Color is normal. Leads to difficulty of start of the engine in cold damp weather and to increase in fuel consumption.
Recommendations: Change candles on new, the same type.

Symptoms: Insulators can be chopped off or burst. Also inaccurate technology of adjustment of a candle gap can lead to damage of the insulator. Can lead to damage of pistons.

Symptoms: After admissions of ignition during a long period of adjournment can be loosened at preservation of working temperature in the combustion chamber. At high speeds of adjournment in flakes come off the piston and stick to the hot isolation center, causing admissions of ignition.
Recommendations: Replace candles or smooth out and establish into place old.

Mechanical damages
Symptoms: Can be caused by hit of foreign materials in the combustion chamber or arise at blow of the piston about too long candle. Lead to refusal of functioning of the cylinder and to damage of the piston.
Recommendations: Remove foreign particles from the engine and/or replace

L OHC 1.2 and 1.4 engines

For simplification of installation mark wire VV with a tape according to the sequence of cylinders with 1 on 4. Sometimes the corresponding marking can be already available on VV wires.


  1. Disconnect wire VV from spark plugs. At the same time pull only for the plug, but not for a cable or use a special stripper.
  2. Turn out spark plugs by means of the corresponding candle key. At the same time you watch that the key did not warp since it can lead to destruction of ceramic isolation of a candle. The Opel company recommends to apply a head of HAZET 900KF 20.8 mm in size to this purpose.

In thermoprotective tubes (engines from 09.1994 g of the issue) spark plugs with a hexagon on 16 mm, as at the DOHC engine are established.

  1. Verify the turned-out candle with the card of states given on a photographic insert that will allow to estimate the general condition of the engine qualitatively.
  2. Before installation of a candle make sure that the carving tip is densely screwed, and a carving on the case and an external surface of a candle are well cleaned.
  3. Installation is made upside-down. Tighten spark plugs with effort of 25 Nanometers.

L DOHC 1.4 and 1.6 engines


  1. Uncover a maslozalivny mouth.
  2. Turn out bolts (1) and extend lock levels of a cover of VV of wires from rubber levels (2) on a head of cylinders Cast away a cover of VV of wires and remove it.

Removal of lock levels of a cover of VV of wires

  1. Close a cover of a maslozalivny mouth.
  2. Remove hoses of PCV (1) and (2).

Removal of hoses of PCV

  1. Disconnect wire VV from spark plugs by means of a stripper which is on one of spark plug sockets.

Wire VV detachment from a spark plug by means of a stripper

  1. Spark plugs on DOHC engines are deeply drowned in candle niches therefore their reversing requires the key drive extender. Having put on a head a candle, connect the drive and, accurately rotating a collar counterclockwise, turn out a candle.

Spark plug reversing from a deep niche by means of a special key
1 — the Neck with the ratchet drive
2 — the Extender
3 — the Cardan hinge
4 — the Candle head with an elastic insert
5 — the Spark plug

  1. Verify the turned-out candle with the card of states given on a photographic insert that will allow to estimate the general condition of the engine qualitatively.
  2. Before installation of a candle make sure that the carving tip is densely screwed, and a carving on the case and an external surface of a candle are well cleaned.
  3. Manually acquire one of new candles in the corresponding opening in the engine. Having made sure that the candle is not warped in a carving, tighten it with the required effort (in the presence of near at hand dynamometer key). For simplification of the procedure of a nazhivleniye of a candle pull a piece of a flexible fuel hose on its shaft. At the same time the probability of failure of a carving as at the slightest zakusyvaniye the hose will begin to be turned simply is excluded. Working in a similar manner, establish all remained candles.
  4. Installation is made upside-down. Spark plugs tighten with effort 25 Nanometers, and bolts of fastening of a cover of VV of wires - with effort of 8 Nanometers.

Features for l DOHC 1.0 and 1.2 engines


  1. Remove the ignition module (see the Head Sistemy of electric equipment of the engine).
  2. Turn out spark plugs a candle key.
  3. Installation is made upside-down.