BMW 3 of the E46 series

since 1998 release

Repair and operation of the car

BMW 3 of the E46 series
+ BMW 3 Cars (E46)
+ Current leaving and service
- Engine
   - Procedures of repair of the engine
      Removal and installation of the lower cover of a motive compartment
      Removal and installation of a box of an air inlet
      Check of a compression
      Removal and installation of the inlet pipeline
      Removal and installation of a head cylinders / replacement of sealing laying
      Removal and installation of camshafts
      Removal and installation of the vacuum pump
      Removal, installation and tension of a maple belt
   + engine Lubrication system
+ Cooling systems, heating
+ Power supply systems, injection and release
+ Electric equipment of the engine
+ RKPP and transmission line
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Schemes of electric equipment

Check of a compression

Check of a compression allows to draw a conclusion on a condition of the engine. During check it is possible to establish, whether valves and pistons (piston rings) are serviceable or they are worn-out. Besides, results of check show, whether it is necessary to replace the engine or it needs to be repaired. For check it is necessary kompressometr.

For check of a compression of the diesel engine it is necessary special kompressometr which is rolled in a carving opening of candles of an incandescence. Check of a compression of the diesel engine is not described here.

The difference between values of pressure of a compression of separate cylinders should not exceed 1.0 bars at the petrol engine, and 3.0 bars at the diesel.

If one or several cylinders in comparison with others have pressure differing on higher value it indicates damage of valves, wear of piston rings or damage of laying of a head of cylinders. In this case the engine needs to be repaired or replaced.

The size of pressure is of secondary importance as it depends among other on the used measuring device. Petrol engines it should have no less than 10 bars.


1 Condition of check is the charged battery.
2 Switch off ignition.
3 Rasstykuyte the main relay of an electronic control system of the engine to exclude injection of fuel during check. The arrangement of the relay of a control system is shown in Specifications of the Head Onboard electric equipment.

If the relay of a control system of the engine is not disconnected, the output step of the main relay of a control system can be damaged.

4 Remove all spark plugs, address to the Section Check of Levels of Liquids.

5 Models 316i, 318i: Rasstykuyte the multi-polar socket of coils of ignition for what turn the handle-1-to the left.

6 Establish manual a check point in neutral situation, automatic in situation "P". Tighten the parking brake.

Do not incline over the engine if it is turned at the removed spark plugs. There is a danger of traumatizing owing to the soot particles which are thrown out thus!

7 Insert or screw kompressometr in a spark plug opening according to the maintenance instruction.
8 Ask the assistant to press completely a pedal of gas and to hold it in such situation during the whole time of check.
9 Turn the engine approximately on 8 turns so that growth of pressure on a kompressometra stopped.
10 Thus, consistently check all cylinders.
11 If the compression in one or several cylinders lies below a wear limit, pour a little motive oil through an opening of a spark plug and again measure pressure the kompressometry. If after that pressure increases, it indicates wear of piston rings and/or a working surface of the cylinder. If pressure does not increase, the valve or sealing laying of a head of cylinders is, as a rule, damaged
12 Establish spark plugs, address to the Section Check of Levels of Liquids.
13 Models 316i, 318i: Join the multi-polar I will corrode ignition coils, thus turn the handle to the right.
14 Install the main relay of a control system of the engine, address to Specifications of the Head Onboard electric equipment.