BMW 3 Series E30

since 1983-1994 release

Repair and operation of the car

+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engine
+ 4. Cooling system
+ 5. Heating and ventilation
+ 6. Fuel system
+ 7. Exhaust system
+ 8. Transmissions
+ 9. Coupling
+ 10. Brake system
+ 11. Running gear
+ 12. Body
+ 13. Electric equipment
- 14. Useful tips
   14.2. The changed numbers
   14.3. Purchase of the old car or mysterious set of figures and letters
   14.4. Durability of the car
   14.5. About parallelism of bridges of the car and trailer
   14.6. Preparation of the car for winter
   14.7. Rule 35
   14.8. Choice of the used car
   14.9. Engine oils
   14:10. What needs to be known, changing oil
   14:11. Emergence in deposit oil
   14:12. Whether it is possible to mix import oils?
   14:13. "Eats" much, but quietly goes
   14:14. It is rather live, than is dead …
   14:15. It is not got - useful tips
   14:16. Visit to car service
   14:17. A gear belt for the gas distribution mechanism drive
   14:18. Wear of pistons
   14:19. Valves
   14:20. Bearings of engines
   14:21. Pollution of the engine
   14:22. As the conditioner works and what to do if it failed
   14:23. Conditioner: not only "pluses", but also "minuses"
   14:24. Rules of service of the conditioner
   14:25. Antifreeze you should not disturb with antifreeze …
   14:26. What should be known upon purchase of the air filter
   14:27. Engine overheat
   14:28. What should be known to the owner of the car with the injector engine
   14:29. Accumulator
   14:30. Possible malfunctions of the rechargeable battery
   14:31. What to do with the failed generator
   14:32. The belt is guilty, and we blame the generator
   14:33. Catalyst
   14:34. Rub in one - or how to save the catalyst
   14:35. Probuksovochka
   14:36. Features of operation of the brake system
   14:37. Malfunctions of the brake system
   14:38. Brake fluids
   14:39. ABS: natural choice
   14:40. Rims
   14:41. We update rims
   14:42. Scheme of marking of a car tire
   14:43. Metal corrosion
   14:44. Automake-up
   14:45. What creaks?
   14:46. Hatch
   14:47. Safety cushion: troubles or pleasures?
   14:48. We fit well?
   14:49. Anticreeping "immunodeficiency"
   14:50. Why headlights grow dull
   14:51. Galogenka
   14:52. About the correct adjustment of headlights
   14:53. Electric motor
   14:54. From change of the places "composed" nothing changes?


14:26. What should be known upon purchase of the air filter


Now our motorist faces a problem – it is necessary to choose. And to choose too it is difficult, market of automobile filters is big. The filter is not the engine and not the crankshaft what difference who made it and what it designs if only performed the functions and cost not much.

From time to time there are novelties in which new designs and materials are used, but happens that they have even no certificate of quality.

The trouble is that the unsuccessful choice of such trifle as, for example, air filter to which and the price of 5 dollars, can ruin the engine and here already expenses are measured not by units, but thousands of dollars.

Purpose of the air filter is clear to all: to block access of dust and to garbage in a working cavity of the cylinder. Hit there of small particles causes intensive wear, and as a result – increase in gaps between the piston and a wall of the cylinder.

Let's consider a design of the ordinary air filter.

The FILTERING CURTAIN is the main working part of any filter, but the filter will not perform the functions if it is not dense, without gaps to become in the case.

The INTERNAL GRID – it is necessary only if sealing trailer disks are made of inelastic rigid material as is that element which helps to keep a surface of a prileganiye of a sealing ring of rather equal. But if on covers of the case there are dents, then the grid will only disturb, holding rigidity of a design and interfering with that the sealant filled these gaps and prevented intake of the crude air.

TRAILER SEALING DISKS – their appointment, first of all, to promote absolute consolidation at a filter clip in the case, not to assume that dirt passed by the filtering curtain. If material of which sealing trailer disks are made is elastic, then and the grid in the filter is not necessary – rigidity of a design is reached by means of stiffening ribs of the corrugated filtering curtain. The elastic sealant without hindrances blocks all cracks and roughnesses on the surfaces of the case.


The main defects which are allowed at production of air filters, leading to premature failure of the engine:

 – use of low-quality filter paper;
 – small area of the filtering curtain (leads to a premature contamination and, as a result, power falls and fuel consumption increases);
 – incorrectly picked up material of sealing disks (insufficiently elastic, fragile at low temperatures);
 – wrong profile of sealing disks (results in impossibility of a dense prileganiye to the case).

Usually the car owner does not penetrate into subtleties of a design of the filter and in own way chooses the filter suitable for it.

Researches showed that at the choice of the filter of buyers interest:

 – reliability of a filtration;
 – reasonable price;
 – trade dress;
 – known trademark.