Subaru Legacy/Outback

1999-2003 of release

Repair and car operation

Subaru Legasi, Autbek
+ Cars Subaru Legacy, Outback
+ The operation manual
+ Routine maintenance
- The engine
   Check компрессионного pressure in cylinders and tightness of the block
   Diagnostics of a condition of the engine with vacuum gauge application
   System of greasing of the engine - the general information
   + The procedures of the repair which has been not connected with extraction of the engine from the car, - four-cylinder engines
   + The procedures of the repair which has been not connected with extraction of the engine from the car, - six-cylinder engines
   + The general and major repairs of engines
+ Systems of cooling, heating
+ The power supply system and release
+ Engine electric equipment
+ Manual box and differential
+ Automatic transmission
+ Coupling
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Check компрессионного pressure in cylinders and tightness of the block

Check компрессионного pressure


 At use компрессометра rolled type the length of a carving part of the nozzle rolled in a candle aperture should not exceed 18 mm!

At carrying out of measurements be cautious, - do not burn about разогретые engine surfaces!

1. Results of check компрессионного pressure in cylinders allow to define the general condition of the components located from lateral aspects of semiblocks (pistons, piston rings, valves, linings of heads of cylinders and so forth) and qualitatively to estimate degree of their deterioration. That is especially important, the analysis of the information received as a result of check allows to narrow a spectrum of the possible reasons of falling of a compression in cylinders, precisely enough having adhered refusal to infringements of functioning of quite concrete components, whether it be piston rings, valves, their saddles or a lining of a head of cylinders

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

2. Make sure of completeness of gymnastics of the storage battery.
3. Warm up the engine to normal working temperature, then turn the ignition switch in position OFF.
4. Dump pressure of fuel (see the Head of the Power supply system and release).
5. Begin with procleaning of candle niches (blow their compressed air as which source in this case the ordinary bicycle pump perfectly will approach), - the main task is prevention of hit of dust in cylinders during performance of measurements.
6. Turn out from the engine all spark plugs (Routine maintenance see the Head).
7. Disconnect electroconducting from injectors of injection of fuel.
8. Fix throttle заслонку in completely open position.
9. Check up serviceability of functioning of a starter.
10. Connect компрессометр to a candle aperture of the first cylinder.

 At use компрессометра with a rolled nozzle the length of a carving part of last should make not more long 18 mm!

11. Turn the engine a starter a minimum on seven turns and consider the measuring instrument indication. On the serviceable engine pressure should accrue quickly enough. Low pressure in the first step, accompanied by its gradual increase in the subsequent, speaks about deterioration of piston rings. If at further проворачивании a shaft pressure does not rise, it can be regarded as the certificate of leaks of valves or infringement of tightness of a lining of a head of cylinders (the probability of presence of cracks in a head is not excluded also). The congestion of adjournment on working facets of plates of valves also can lead to decrease компрессионного pressure. Write down the maximum indication компрессометра at steady position of the index. Measurements spend, at least, twice.

12. Repeat procedure for the remained cylinders of the engine. Compare results to standard requirements (Specifications see).
13. At excessively low results of measurement, fill in in each of cylinders through a candle aperture a little impellent oil (two-three teaspoons) and repeat check.
14. If oil addition leads to pressure increase, it speaks about deterioration of piston rings. If the compression does not increase, the reason of its decrease are leaks of valves or infringement of tightness of a lining of a head. Leaks of valves can be connected with a burn-out of their saddles, either deformation/burn-out or mechanical damages of working facets.
15. If pressure of compression is equally underestimated in two next cylinders with high degree of probability it is possible to speak about infringement of integrity of a lining of a head within its crosspiece between the given cylinders. Presence of a cooling liquid at impellent oil will confirm the given assumption.
16. If pressure in one of cylinders approximately on 20 % more low, than in other and it is accompanied by infringement of stability of turns of idling, it is necessary to estimate degree of deterioration of cams of a drive of corresponding valves on a camshaft.
17. Unusual overestimate компрессионного usually is a consequence of pressure excessive нагарообразования in combustion chambers. In this case the head of cylinders should be removed for the purpose of carrying out декарбонизации.
18. At excessively low results of measurements, and also in case of infringement 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 centre workshop. Such check will allow to define precisely a source of leak and to estimate degree of its gravity.
19. Establish into place safety locks and make on the car a short trip for the purpose of restoration written down in memory of the processor of adjusting parametres.

Block check on leaks


1. 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.
2. The equipment necessary for check on leaks, is not among popular, therefore performance of the given check should be entrusted experts of the service centre.

On the main page