BMW 5 Series E39

since 1996-2001 release

Repair and operation of the car

+ Introduction
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Cooling systems, heating
+ Power supply system and release
- Engine electric equipment
   - System of ignition
      Security measures during the work with system of ignition
      Removal and installation of the coil of ignition
      Removal and installation of the sensor of a detonation
      Check and replacement of the sensor of impulses
      Removal and installation of the plug of a spark plug
      Removal and installation of the DME control unit
      Spark plugs
   + System of preheat of the diesel engine
   + Systems of a charge and start
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Schemes of electric equipment
+ System of onboard diagnostics

Spark plugs

General description and parameters

Spark plugs have the turnkey size of 16 mm. Producers recommend candles of a certain type, however it is possible to use suitable candles with the corresponding kalilny number of other producers. Spark plugs should be replaced through each 20 000 km or 2 years. Before a vyvinchivaniye of candles check that in niches of candles there were no foreign objects. The washers which got to openings of candles, bolts or stones will destroy valves, saddles of valves or a head of cylinders at the first start of the engine.

The spark plug consists of the central electrode, the insulator with the case and a side electrode. The central electrode is hermetically connected with the insulator, the insulator is strongly connected with the case. The spark is formed between the central and side electrodes. Starting readiness, characteristics of idling, acceleration and the maximum speed of the car depend on a spark plug. Thereof it is not necessary to apply candles, other than those which are recommended by manufacturer. Key parameter of a spark plug is the kalilny number. It characterizes thermal load ability of a candle under certain conditions of operation. Candles are chosen in such a way that they under all possible service conditions reach self-cleaning temperature. The kalilny number of a candle is lower, the higher it resistance in relation to kalilny ignition and the is higher resistance to pollution.

The Kalilny number is specified in a candle code. The code has the following structure:

For example

Bosch candles

F 8 L


1 2 3

4 5 6

1 — W - a carving of M 14 x 1.25 with flat consolidation, on a turn-key basis 21; F - a carving of M 14 x 1.25 with flat consolidation, on a turn-key basis 16; H - a carving of M 14 x 1.25 with conical consolidation, on a turn-key basis 16.

2 — Kalilny number. Can be from 06 (a "cold" candle) to 13 (a "warm" candle). At the same time number 8 corresponds to kalilny number 150 (former designation), 7 - 175, 6 - 200 etc.

3 — B - length of a carving is 12.7 mm, a vystupaniye of a thermal cone of the insulator for a case end face; With - length of a carving is 19 mm, the normal provision of a thermal cone; D - length of a carving is 19 mm, a vystupaniye of a thermal cone of the insulator; L-length of a carving of 19 mm, the raised vystupaniye of a thermal cone.
The carvings given about length belong to candles with flat consolidation. In addition "T" (for example, "DT") - 3 electrodes of weight.

4 — Execution of an electrode

5 — Material of the central electrode: without data - chromonickel alloy, With - copper-nickel alloy, S - silver, Z - platinum.

6 — With a noise suppressing resistance.

The spark plugs applied to BMW of the 5th series are given in Specifications.

In the course of technical development new types of candles can appear. Advice about characteristics of candles can be got in specialized workshops.

Condition of candles as characteristic of quality of operation of the engine

On appearance of a candle it is possible to draw a conclusion on work of candles, adjustment of system of injection, quality of mix and wear of the engine (pistons, piston rings, etc.). Address photographic inserts.

At a vvinchivaniye of candles you watch that they were not drawn as the sealing washer can be damaged. Do not exceed the moment of an inhaling of 25 Nanometers.


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 resilience


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, 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
As service life of candles usually makes 15 000 km, it is enough to clear of them through each 8000 km of a run.