Audi A4

since 1994 release

Repair and operation of the car


A4 Audi
+ Running gear
+ Regular servicing
- Engines
   Power steps
   Engine signs
   Technology of the engine, maintenance and repair
   Lubrication system
   Exhaust ventilation of a case
   Visual control of the engine
   Engine service life
   Nominal and maximum frequency of turns
   Restriction of number of turns
   Measurement of pressure of compression
   The help at malfunctions
   Hydropushers
   Works on a gear belt
   The help at malfunction
   Installation and dismantle of a head of the block of cylinders
   Installation and dismantle of the engine
+ Turbo-supercharging
+ System of an exhaust
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and channels of absorption
+ System of injection
+ Coupling
+ Transmission and main transfer
+ Suspension bracket of wheels and steering
+ Brakes
+ Wheels and tires
+ Electrotechnical equipment
+ System of ignition
+ Lighting
+ Alarm equipment
+ Tools and devices
+ Heating and ventilation
+ body Details
+ Salon
Search of malfunctions
Technical characteristics



Hydropushers

For what hydropushers serve?

Due to heating of the engine separate details of valvate mechanisms extend and extended. Therefore in order that valves kept tightness, despite the little extended cores, between a cam-shaft and tarelochny pushers there has to be a small side play or a gap. This side play – a so-called valvate gap – in old models of cars had to be regulated through certain periods. In Audi A4 at each actuating of the valve it occurs automatically due to so-called hydraulic alignment of a valvate gap which is carried out by tarelochny pushers. From here and name "hydropushers".

Actuating of valves by means of hydropushers: oil under a high pressure is represented in the red color. By pink color the amount of oil which is not used for actuating of valves is designated. Are designated by figures:

1 – cam-shaft cam;
2 – space of an oil collector;
3 – returnable valve;
4 – oil supply;
5 – chamber of a high pressure;

6 – valve core;
7 – press spring;
8 – cylinder;
9 – piston;
10 – hydropusher.

Noise in valves

Knock in valves in the field of a head of the cylinder can indicate one or several defective hydropushers.

But noise in the valve can arise and at serviceable hydropushers, if:

  • shortly before start of the engine supply of oil on hydropushers was not provided yet;
  • the car before it moved with full loading at high external temperature;

  • long did not go by the car. Noise has to disappear at achievement by the engine of working temperature;
  • at extremely low level of oil the oil pump sometimes sucks in air.

Definition of a defective hydropusher

 PERFORMANCE ORDER

  1. Start the engine, and let it work, will not reach working temperature yet.
  2. Lift turns for 2 min. approximately to
    2500 rpm.
  3. If noise in valves does not disappear, switch off the engine and dismantle a head of the block of cylinders.
  4. Turn the cylinder No. 1 in ignition moment VMT.
  5. Wring out all tarelochny pushers of the cylinder No. 1 a wooden klinyshk down. If at the pressed hydropusher it is possible between it and a cam-shaft to insert a template thickness
    0,20 mm, replace a pusher.
  6. Repeat the same process on other cylinders. For this purpose put each cylinder in VMT. This situation when at the checked cylinder all cams of a cam-shaft are equally turned up.

 Council: For replacement of a defective tarelochny hydropusher it is necessary to dismantle a cam-shaft. After installation of a new tarelochny pusher within 30 min. it is impossible to start the engine! The Tarelochny pusher has to "sit down". Otherwise valves will strike on the piston.


For check of hydraulic pushers it is necessary to press a plastic or wooden wedge (1) the unloaded hydraulic pusher (2). Metal tools with which it is possible to scratch easily a pusher surface, cannot be used.