2000 Audi A8 Quattro A/C & Heater Service (ONLINE REPAIR MANUALS)

• Before beginning test, ensure following conditions exist:
• Condenser and radiator are clean and free of obstructions.
• Accessory drive belt is in good condition and is properly tensioned.
• All air ducts, covers and seals are in good condition and correctly installed.
• Vehicle is not parked in direct sunlight.
• Engine at normal operating temperature.
• Coupling between evaporator housing and heater box tight and does not draw, secondary air at high fresh air blower speed.
• With engine running, system in "AUTO" operating mode...

A4

• On models with audio coded anti-theft system, refer to "Precautions."
• On all models, recover refrigerant as outlined under .
• Remove right air plenum cover, then the water guide.
• Remove dust and pollen filter air plenum hosing.
• Open cap at coolant system expansion tank.
• Clamp coolant hoses, then remove hoses from heater core inlet/outlet, Fig. .
• Place a suitable catch basin below heater core connection "A," then blow coolant out of heater core with compressed air through connection "B."
• Remove A/C system vacuum supply hose from e...

A4

• On models with audio coded anti-theft system, refer to "Precautions."
• On all models, recover refrigerant as outlined under .
• Remove right air plenum cover, then the water guide.
• Remove dust and pollen filter air plenum hosing.
• Open cap at coolant system expansion tank.
• Clamp coolant hoses, then remove hoses from heater core inlet/outlet, Fig. .
• Place a suitable catch basin below heater core connection "A," then blow coolant out of heater core with compressed air through connection "B."
• Remove A/C system vacuum supply hose fr...

Air Bag II & III System

The system must be disarmed prior to disconnecting any air bag system electrical connectors or servicing any system components or other components located near an air bag system electrical connector. Obtain the radio security code prior to disconnecting the battery ground cable. Establishing the engine control module and automatic transmission control module settings may be required using scan tool No. VAG 1551, or equivalent.

• Disconnect battery ground cable and cover negative terminal.
• On 1990-92 Coupe, Quattro, 80/90 and 19...

A4

1.8L Engine

• Remove front bumper.
• Unbolt cooling pipe for power steering hydraulic oil.
• Place suitable drip tray underneath engine.
• Open coolant expansion tank cap.
• Turn radiator drain plug counterclockwise, if needed attach accessory hose to connection flange.
• Remove coolant hoses at radiator and remove clip from connecting flange.
• On models equipped with automatic transmission, remove ATF lines from radiator.
• On all models, remove air guide retaining bolts at lefthand and righthand sides.
• Remove retaining ...

Testing the refrigerant system for leaks is one of the most important phases of troubleshooting. One or more of the methods outlined will prove useful in detecting leaks or checking connections if service work is performed. Before beginning any leak test, attach a manifold gauge set and note pressure. If little or no pressure is indicated, a partial charge must be installed. Check all connections, compressor head gasket, oil filler plug and compressor shaft seal for leaks.

R-12 leak detectors will not detect R-134a leaks. For R-134a system an electronic type leak detector i...