2000 Volkswagen Passat A/C & Heater Service (ONLINE REPAIR MANUALS)

Cabrio & 1998 Golf & Jetta

• Disconnect thermo-time switch connector and remove thermo-time switch, then fully open heater valve.
• Add coolant to expansion tank until coolant flows from thermo-time switch opening, then install and connect thermo-time switch.
• Fill coolant expansion tank to MAX mark, then install expansion tank cap.
• Run engine until cooling fan comes on, then check coolant level.
• Coolant level should be at or slightly above MAX mark with engine at normal operating temperature, and between Min and Max. marks with engine cold.
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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...

Use instructions provided with charging station. Follow these procedures to prevent charging station from being accidentally exposed to high-side vehicle system pressure:

• Do no...

While a detailed diagnostic procedure for all air conditioning systems would be impractical due to the many variations in construction and operation, there are three fundamental components of a total diagnosis:

• Refrigerant systems must have an adequate, but not excessive charge.
• Determination must be made whether the refrigerant system is governed by a cycling clutch compressor or by valves which control evaporator pressure.
• The air distribution system (blower motor, switches, vacuum lines and air ducts) must be operational before checking the ...

Using Vacuum Pump

Vacuum pumps suitable for removing air and moisture from A/C systems are commercially available. A specification for system pump down used here is 28-29^1/2 inches vacuum. This reading can be attained at or near sea level only. For each 1000 feet of altitude this operation is performed, the reading will be 1 inch vacuum higher. For example, at 5000 feet elevation, only 23-24^1/2 inches of vacuum can be obtained. The system refrigerant must be completely recovered before it can be evacuated. Damage to the vacuum pump will result if pressurized ...