Audi A4

Since 1994 of release

Repair and car operation

At the left: by arrows four high-speed shutters which facings at removal of the six-cylinder engine should be turned to the left on 90 are shown.

On the right: in the six-cylinder engine the cover of a gear belt fastens two clips (arrow). To dismantle the right cover of a gear belt, it is necessary to remove in addition a tension roller поликлинового a belt (the big bolt with internal шестигранником).

Too low indicators of pressure

Indicators of equally low pressure of compression yet an occasion to anxiety; the admissions of measurements different for different devices can be the reason of low indicators. But if at gaugings on different cylinders the difference makes more than 3 bar, it is necessary to reflect. It can mean the following:

• Deterioration of pistons and piston rings;
• Piston rings densely sitting in flutes as consequence of pollution;
• Cylinders of not round form as consequence of jamming of pistons;
• Adjournment on cores of valves or saddles of valves at the expense of burning and greasing products;
• The burnt down valves. In most cases the reason of insufficient pressure of compression are not tight valves and, hence, the lowered capacity of the engine. Repair of a head of the block of cylinders can help only.

Search of malfunctions

For defect localisation at too low pressure of compression use reception: a manual butterdish drip a few engine oil in a nest of a spark plug and once again measure pressure of compression.

• If indicators and now below norm, valves are not perfectly in order.
• If indicators became above, business in piston rings and, maybe, in cylinders. The filled in oil for a short while has worked as a lining between the piston and cylinder walls so the compressed gas almost did not find an exit.

The test for pressure loss (on tightness)

More exact results are given by the test for tightness which some workshops can spend. If the checked chamber of combustion loses pressure it is shown on a tester scale.

Larger place of leak can be defined listening:

• Шипенье in an exhaust pipe testifies to leaky closed final valve.
• Вытекание air from the case of the air filter testifies to defect of the inlet valve.
• At a defective lining of a head of the block of cylinders or a crack in a head of the block of cylinders the compressed air arrives through the next nest of a spark plug or from an open broad tank with a cooling liquid outside.
• The worn out walls of the cylinders, directing pistons or piston rings pass pressure in картер, and it leaves from opened маслозаливного a branch pipe or a tube for probeа measurements of level of oil.

Engine scrolling

Cylinder installation № 1 in the top dead point of the moment of ignition

In the four-cycle engine the piston during four working steps two times reaches the top dead point (ВМТ): once at ignition of the let in mix, in the second time – after emission of the fulfilled gases, with an admission of a toplivno-air mix beginning right after it. Usually at various adjusting works position ВМТ of the cylinder № 1 is required.

Dismantle of facing of the engine

Dismantle of facing of a klinovo-ridge belt

The 6-cylinder engine

The poliklinovoj belt in the six-cylinder engine works under facing on the face-to-face party of the engine.

Dismantle of a cover of a head of the block of cylinders