Audi Workshop Service and Repair Manuals > A4 Mk3 > Power unit | Direct petrol injection and ignition system (4-cyl. 1.8 ltr. 4-valve turbo with timing chain) | Mixture preparation system, electronic inj.,Gas | Air cleaner

Removing air cleaner housing

Removing

–	Unplug electrical connector -1- at air mass meter -G70-.

–	Release hose clip -2- securing air hose (going to turbocharger) and disconnect hose from air mass meter -G70-.

–	Remove air duct -3-.

–	Detach vacuum hose -arrow- (if fitted).

–	Release retainer -4- for bottom section of air cleaner (press in rubber on left and right side and pull upwards).

Note

t	These components (bypass flap with variable intake manifold change-over valve -N335--1-) are not installed on certain equipment versions or on vehicles for certain export markets.

t	Do not use lubricant when installing retainer.

–	Disconnect electrical connector at variable intake manifold change-over valve -N335- (if fitted).

–	Carefully take out complete air cleaner housing.

Installing

To ensure the proper function of the air mass meter -G70- it is important to observe the following instructions.

Note

t	If the air filter element is very dirty or wet, dirt or water could reach the air mass meter -G70- and affect the air mass value. This would lead to loss of power, since a smaller injection quantity is calculated.

t	Always use genuine part for air filter element.

t	Use a silicone-free lubricant when installing the intake hose.

t	Secure all hose connections with the correct type of hose clips (same as original equipment) → Parts catalogue

–	If warm air intake hose is fitted (for countries with cold climates only), make sure that air intake connection has engaged properly -arrows- (pay attention to markings).

–	Check water drain hose -1- in air cleaner (bottom section) for dirt and other obstructions (clean if necessary).

–	Clean salt residue, dirt and leaves out of air cleaner housing (top and bottom sections); use a vacuum cleaner if necessary.

–	Check for salt residue, dirt and leaves in air mass meter and air intake hose (engine intake side).

–	Check for dirt in air duct leading to air filter element.

–	Re-attach electrical connector at variable intake manifold change-over valve -N335- (if fitted).

–	Re-install air cleaner (bottom section).

Note

The water drain hose must be routed straight downwards without kinks.

–	Slide vacuum hose -3- (if fitted) back onto connection of variable intake manifold change-over valve -N335--1-.

–	Fit the top section of the air cleaner carefully on the bottom section, without using force.

Note

Before tightening bolts, make sure that top section of air cleaner is inserted into groove on bottom section of air cleaner (to prevent air leaks).

–	Then screw top section of air cleaner back onto bottom section.

–	Ensure secure fit of intake hose at air mass meter -G70-.

–	Re-connect electrical connector at air mass meter -G70-.

–	The remaining installation steps are carried out in the reverse sequence.

Audi Workshop Service and Repair Manuals