Withdrawal
Remove bolt -1-.
Open quick locks (arrows) and remove the air filter cover.
Pull out the filter element.
Loosen the nuts (arrows) attaching the air filter housing.
Remove fastener -H.
Loosen nut -1- for intake system support.
Detach the outside air hose -2- and the warm air hose -1-, after fully releasing the clamps -S-.
Detach hose -E- for crankcase breather, hose for auxiliary air metering valve in over idle mode and vacuum hose at lower part of air cleaner housing.
Remove the air filter housing.
Installation
Connect the crankcase breather hose, the hose for the over-idling air dosing valve, and the vacuum hose at the bottom of the air filter housing.
Position the air filter housing, fit the retaining ring and screw it down.
Attach the intake system support to the bracket.
Connect the outdoor air hose and warm air hose, securing with clamps.
Insert filter element.
Position the cover so that the arrows -2- and -3- in figure W-2014 point towards each other.
Screw on the air filter cover and secure with quick-release fasteners.
Intake air heating test
The intake air heating is temperature dependent and controlled by an air damper in the air intake. In the event of a defect in the heating system, the following malfunctions may occur:
- Violations of the idling mode during the warm-up phase.
- Transient disturbances.
- Insufficient power, maximum speed does not develop.
- High fuel consumption.
Checking the position of the air damper
The position of the air damper is monitored through the sight glass -2- in the air intake -3-.
When the engine is running cold, the damper must open the warm air duct -4- so that warm air flows from the exhaust manifold to the air filter.
When the engine warms up, the air damper gradually closes the warm air channel and at the same time opens the outside air channel.
When the operating temperature of the engine is reached, the warm air channel is completely blocked. Only outside air enters the engine. Otherwise, check the membrane box.
Diaphragm box check
Check the tightness of the fastening of the vacuum hoses between the membrane box and the temperature controller and between the temperature controller and the intake manifold.
Bending the hoses, check for cracking and damage; if necessary, replace damaged hoses.
Disconnect the hose -5- from the temperature controller -6- at the bottom of the air filter housing and check the operation of the air damper by sucking it in with your mouth. If the flap opens, clean the openings -E- and -F- of the temperature controller (drawing W-2015). If required, replace the temperature controller.
If the air damper remains closed, replace the membrane box.
At the service station, a vacuum pump with a pressure gauge connected is used to check the diaphragm box. The pump is connected to the hose -5- and thus creates a vacuum at the membrane box. Up to vacuum values of 70±10 mbar, the warm air duct must remain closed, from 140±10 mbar it must be open. In the removed position, the setting lever of the membrane box must be completely recessed at a vacuum of about 300 mbar and the vacuum must not fall.