BMW 5 series E39

1. Before the work beginning prepare all necessary tools which include a replaceable head of a candle key of 16 mm and a set of edges щупа. Some manufacturers of spark plugs deliver special tools for measurement of a candle backlash. The spark plugs applied on BMW are resulted in Specifications.
2. The best way of replacement of spark plugs is preliminary purchase of new candles, adjustment of their backlash and replacement of each candle by turns. At purchase of candles very important to choose those candles which are intended for the engine of your car. The information on them can be received in Specifications to the Head an engine Electric equipment.
3. Having near at hand new candles, allow to the engine to cool down completely before the beginning of removal of the old. In this time it is possible to examine new candles on presence in them of defects and to check up candle backlashes.
4. The candle backlash is checked by insertion of a measuring instrument of the necessary thickness between electrodes on the candle end. The backlash should correspond specified in Specifications. The delay should concern only each of electrodes. If the backlash does not correspond to norm, slightly turn in the bent part of an electrode by means of a regulator with notches before achievement of necessary size of a backlash.

At adjustment of a backlash of a new candle turn in only the basis of an electrode of grounding, without touching its end. If the grounding electrode is displaced concerning the central electrode, by means of a regulator with notches level them. Check up a porcelain insulator on presence of the cracks specifying that it is necessary to replace a candle.

5. At the cooled engine remove ignition coils, address to Section Removal and installation of the coil of ignition.
6. If there is such possibility, use compressed air for blowing of a dirt and particles of alien materials from area round spark plugs. It is possible to use for this purpose the usual bicycle pump. It becomes on purpose to avoid possibility of hit of dust in the cylinder after extraction of candles.
7. Establish a head of a candle key on a candle and remove a candle from the engine, having unscrewed it counter-clockwise.
8. Compare the taken out candle with shown on pictures in the Head an engine Electric equipment, it will give you the helpful information on the general condition of the engine.
   a) Grey colour of electrodes and an insulator of average density - correct work of a candle and an optimum working mix.
   b) Black colour of electrodes and an insulator - a mix too rich.
   c) Light grey colour of electrodes and an insulator - a mix too poor.
   d) Zamaslivanie of electrodes and an insulator - work of a candle with faults or bad consolidation of piston rings (check up a compression).
9. Check up a candle insulator on presence of traces of currents of leak. Leak currents are shown in the form of thin any traces on an insulator surface. Leaky contact of the tip of candles can be the reason of currents of leak. In this case штекерное it is necessary to replace connection.
10. Put a little медьсодержащего antitaking structure on a carving of a new candle. Insert a candle into a head of cylinders and screw its fingers against the stop, then tighten by means of a head of a candle key. If it is possible, use for a candle tightening динамометрический a key to be assured that it is established correctly. The effort of a tightening of candles is included in Specifications.

11. Establish coils of ignition and an engine cover. Thus watch correct connection of tips and connection with weight, address to Section Removal and installation of the coil of ignition.
12. Repeat the procedure described above for other spark plugs consistently to avoid wrong connection.