Audi A4, S4

Since 2000 of release

Repair and car operation

Audi A4, S4
+ Introduction
+ Controls and receptions of safe operation
+ Current leaving and service
- The engine
   Removal and installation of the top cover of the engine / the bottom protection of an impellent compartment/stretcher
   Compression check in engine cylinders, revealing of leaks
   Check of the engine by means of the vacuum gauge
   + 4-cylinder petrol engines
   + 6 and 8-cylinder petrol engines
   + 4-cylinder diesel engines
   + 6-cylinder diesel engines
   + System of greasing of the engine
+ Systems of cooling, heating and the air conditioner
+ Power supply systems, release and decrease in toxicity of the fulfilled gases
+ Systems of an electric equipment of the engine
+ Manual box of a gear change
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Compression check in engine cylinders, revealing of leaks

Compression check

The compression provides guidance on an engine condition. Results of check show, whether valves and pistons (piston rings) are perfectly in order, or they are worn out. Whether Besides, results of check allow to make decision to replace the engine, whether the complete repair is required to it or to replace a sealing lining of a head of cylinders enough. For check it is required компрессометр which for petrol engines is offered in specialised shops under the reasonable price.

For diesel engines it is necessary компрессометр with a limit of measurements approximately to 40 атм.

The engine should be heated-up to working temperature, the storage battery — is completely charged. The help of the assistant also is required to you.

As much as possible admissible difference of pressure in separate cylinders can make 3.0 атм. (For diesel engines 5.0 атм.).

Pressure of a compression grows in the serviceable engine very quickly. The low value shown after the first cycle, increasing with the subsequent cycles, specifies in deterioration of piston rings. Low value after the first cycle, not increasing after the following, signals that or valves негерметичны, or the lining of a head of the block (by the reason also is punched there can be a crack in a head). In compression decrease can result deposit presence on plates of valves.

It is necessary to mean that because of different speed of rotation of a starter on different models the results received as a result of measurements can differ. The results received at measurement of a compression, should be about identical to all cylinders.

If pressure is in any cylinder at level minimum admissible and even more low for reason finding-out execute to a trace ющие actions. Pour in in the cylinder through an aperture for a candle a teaspoon of impellent oil and repeat compression measurement.

If oil addition has temporarily improved a compression, the reason of its decrease, most likely, is deterioration of the piston, rings or the cylinder. If the compression increase has not occurred, it is possible to assume that the reason — in негерметичности valves or the punched lining of a head of the block.

Low compression in two next cylinders almost for certain — a consequence of breakdown of a lining of a head. Presence of a cooling liquid in chambers of combustion or in картере the engine will confirm this assumption.

If a compression in one of cylinders approximately on 20 % more low, than in the others, besides idling turns are astable, the reason, probably, excessive deterioration of a cam of a cam-shaft.

After check end establish to the place of a spark plug (address to the Head Current leaving and service, put on them tips of high-voltage wires, attach a socket to the ignition coil. Establish into place a plastic cover of the engine and a safety lock of the fuel pump.

Values of pressure of a compression for various engines are resulted in Specifications.

The petrol engine


  1. Switch off ignition.
  2. The engine of 1.6 l: Disunite a socket of a target step of the coil of ignition. The target step is in one case with ignition coils on the engine.
  3. Take out a safety lock № 28 fuel pumps.
  4. The engine of 1.8 l: Disunite sockets of coils of ignition and injectors.
  5. Engines 2.0, 2.4 and 3.0 l: Remove ignition coils. Disunite a socket of injectors.
  6. Remove all spark plugs, address to Section Check and replacement of spark plugs. Check of a condition of high-voltage wires.

At проворачивании the engine be not declined over the engine. There is a danger травмирования owing to emission of particles of soot.

  1. Turn the engine a starter to remove a deposit and soot.

Establish a check point in neutral position and tighten a lay brake.

  1. Screw компрессиометр according to a management of the manufacturer in an aperture for a candle.
  2. Ask the assistant to press a pedal of gas and during check to keep her foot.
  3. Turn the engine approximately on 8 turns so that on компрессиометре any more there were no pressure throws.
  4. Consistently check up all cylinders and compare the received values of pressure to the set.
  5. Establish to the place of a spark plug and fix their moment 30Нм, address to Section Check and replacement of spark plugs. Check of a condition of high-voltage wires.
  6. Again join all disunited sockets, if necessary, insert into place a safety lock.

At рассоединении sockets in the block of management of the engine the data about malfunctions registers. It is recommended to remove as soon as possible the written down data on HUNDRED AUDI.

Diesel engines


  1. The engine of 1.9 l: Disunite the central tip of the engine. For this purpose turn to the left the screw with a notch. Disunite a socket of spark plugs.
  2. The engine of 2.5 l: Disunite socket ТНВД.
  3. Remove all candles накаливания, address to Section Removal and installation of candles накаливания.
  4. Screw компрессиометр with flexible joining instead of candles накаливания.

The values of a compression specified in Specifications correspond to measurement with the help компрессометра V.A.G. In case of application of other measuring devices deviations are possible. In this case it will be possible to measure only disorder of pressure on separate cylinders.

  1. Turn the engine approximately on 8 turns so that on компрессиометре any more there were no pressure throws.
  2. Establish to the place of a candle накаливания and fix their moment 15Нм. Attach a wire.
  3. Join and fix all sockets.

At рассоединении sockets in the engine management block the data about malfunctions registers. It is recommended to consider and remove the written down data as soon as possible.

Check on leaks

During the given check are defined speed of an exit from cylinders закачанного in them of the compressed air and it is direct places of leaks. The given check is alternative to compression check. Moreover, from many points of view it is much more effective as visually to reveal a source of leak easier, than to comprehend results of measurement of a compression.

The equipment necessary дляпроверки on leaks, does not concern to popular, therefore performance of the given check should be entrusted experts of the service centre.