Opel Astra, Zafira

since 1998 of release

Repair and car operation

Opel Astra
+ Opel Astra and Zafira Cars
+ Operation manual
+ Routine maintenance
- Engine
   Check of kompressionny pressure in cylinders
   Diagnostics of a condition of the engine with use of the vacuum gage
   + Procedures of repair of petrol SOHC engines without their extraction from the car
   + Procedures of repair of petrol DOHC engines without their extraction from the car
   + Procedures of repair of diesel engines of 1.7 l and 2.0 l without their extraction from the car
   + General and major maintenance of the engine
+ Systems of cooling, heating
+ Power supply system and release
+ engine Electric equipment
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Check of kompressionny pressure in cylinders

Results of check of kompressionny pressure in cylinders allow to define the general condition of components of the top part of the engine (pistons, piston rings, valves, laying of a head of cylinders, etc.) and qualitatively to estimate degree of their wear. That is especially important, the analysis of information received as a result of check allows to narrow a range of the possible reasons of falling of a compression in cylinders, rather precisely having adhered refusal to violations of functioning of quite concrete components, whether it be piston rings, valves, their saddles or head laying.

The engine should be heated-up to normal working temperature, and the storage battery is completely charged.


  1. Begin with pro-cleaning of candle niches (blow them the compressed air as which source in this case the ordinary bicycle pump perfectly will approach). The main objective is prevention of hit of garbage in cylinders during performance of measurements.
  1. Dump pressure in a power supply system (see. Head of the Power supply system and release). Disconnect a power supply system by extraction from the assembly block of the relay of the fuel pump established in an impellent compartment.

On diesel engines release a latch and disconnect electroconducting from the TNVD control unit that the razbryzgivaniya of fuel will allow to avoid and to eliminate risk of spontaneous start of the engine.

  1. Turn out from the engine all candles of an ignition / incandescence (see. Head Routine maintenance). Fix a butterfly valve in completely open situation.
  2. On the models equipped with the distributor of ignition, disconnect from a cover of the last central (a bobbin wire) and earth it on the engine block. On models without the distributor disconnect electroconducting from each of ignition coils.
  1. Establish компрессометр in a candle opening of the first cylinder — it is preferable to use to connection компрессометра a nozzle carving, instead of clamping type. Do not forget to open during check against the stop a butterfly valve.

    A — Check of kompressionny pressure in the third cylinder of the petrol engine
    B — Check of kompressionny pressure in the first cylinder of the diesel engine



In diesel engines extent of compression is much higher, than in petrol therefore check of kompressionny pressure will need special компрессометр with a measurement range not less the 40th bar. Kompressometr is rolled by the transitional nozzle in a glow plug opening, or established instead of a nozzle of injection of fuel. In view of features of a design of the nozzles used in diesel engines considered in the real Management, компрессометр it is necessary to roll in candle openings.

  1. Turn the engine at least on seven steps and consider the measuring instrument indication. On the serviceable engine pressure should accrue quickly enough. Low pressure on the first step, being accompanied its gradual increase on the subsequent, speaks about wear of piston rings. If at a further provorachivaniye of a shaft pressure does not rise, it can be regarded as the certificate of leakages of valves or violation of tightness of laying of a head of cylinders (the probability of existence of cracks in a head is not excluded also). The congestion of deposits on working facets of plates of valves also can lead to decrease in kompressionny pressure. Write down the maximum indication компрессометра.
  2. Repeat procedure for the remained cylinders of the engine. Compare results to standard requirements (see. Specifications).
  3. At excessively low results of measurement fill in in each of cylinders through a candle opening of a little impellent oil (two-three teaspoons) and repeat check.

If addition of oil leads to pressure increase, it speaks about wear of piston rings. If the compression does not increase, the reason of its decrease are leakages of valves or violation of tightness of laying of a head. Leakages of valves can be connected with a burn-out of their saddles, either a deformation / burn-out or mechanical damages of working facets.

If pressure of compression is equally underestimated in two next cylinders, with high degree of probability it is possible to speak about violation of integrity of laying of a head within its crossing point between these cylinders. Presence of cooling liquid at impellent oil will confirm this assumption.

If pressure in one of cylinders approximately for 20 % is lower, than in other and it is accompanied by violation of stability of turns of idling, it is necessary to estimate degree of wear of cams of a drive of the corresponding valves on a camshaft.

Unusual overestimate of kompressionny pressure usually is a consequence of an excessive nagaroobrazovaniye in combustion chambers. In this case the head of cylinders should be removed for the purpose of carrying out a dekarbonizatsiya.

At excessively low results of measurements, and also in case of violation of uniformity of distribution of pressure between cylinders it will be useful to hold testing of the engine for leaks in the conditions of a car-care center workshop. Such check will allow to define precisely a source of leak and to estimate degree of its gravity.

Block check on leaks

During this check are defined speed of an exit from cylinders of the compressed air pumped in them and directly a place of leaks. This 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 simpler, than to comprehend results of measurement of a compression.

The equipment necessary for check on leaks, is not among public therefore performance of this check should be entrusted specialists of the service center.