Volkswagen Front Wheel Drive 1974-1989 Repair Guide

Intake Manifold

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REMOVAL & INSTALLATION



Carbureted Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner. Drain the cooling system.
  4.  
  5. Disconnect the accelerator cable.
  6.  
  7. Label and disconnect the EGR valve connections.
  8.  
  9. Label and unplug all electrical leads.
  10.  
  11. Disconnect the coolant hoses.
  12.  
  13. Disconnect the fuel line from the carburetor.
  14.  
  15. Label and disconnect the vacuum hoses from the carburetor.
  16.  
  17. Loosen and remove the retaining bolts, then lift the manifold off the engine.
  18.  

To install:
  1. Install a new gasket. Fit the manifold and tighten the bolts from the center working outwards. Tightening torque is 18 ft. lbs. (25 Nm).
  2.  
  3. Connect the vacuum hoses to the carburetor.
  4.  
  5. Connect the fuel line to the carburetor.
  6.  
  7. Connect the coolant hoses.
  8.  
  9. Connect all electrical leads.
  10.  
  11. Connect the EGR valve.
  12.  
  13. Connect the accelerator cable.
  14.  
  15. Install the air cleaner and refill the cooling system. Start the engine and check for leaks.
  16.  

CIS/CIS-E Fuel Injected Engines (Except 16-Valve)

See Figures 1, 2 and 3

  1. Disconnect the negative battery cable.
  2.  
  3. Disconnect the air duct from the throttle valve body. Drain the cooling system.
  4.  
  5. Disconnect the accelerator cable.
  6.  
  7. If necessary, remove the injectors and position them aside. Cap the injectors to prevent any entry of dirt. Disconnect the line from the cold start valve. Have a small plastic container handy to catch the excess fuel.
  8.  
  9. Disconnect all coolant hoses.
  10.  
  11. Disconnect all vacuum and emission control hoses. Label all hoses for ease of installation.
  12.  
  13. Remove the auxiliary air regulator.
  14.  
  15. Unplug all electrical connectors. Label all wires for installation.
  16.  
  17. Disconnect the EGR line from the exhaust manifold.
  18.  
  19. Loosen and remove the retaining bolts and lift off the manifold with the throttle body attached. It is easier to remove the throttle body with the intake manifold off the engine. Clean the intake manifold gasket mating surfaces thoroughly. Make sure that all traces of the old gasket material are removed. Inspect the intake manifold for cracks and the gasket surfaces for warpage. If the manifold is damaged, replace it.
  20.  



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Fig. Fig. 1: On some models, it will be necessary to use a special Allen head socket to remove the manifold attaching bolts



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Fig. Fig. 2: Carefully lift the manifold from the engine. Be careful not to damage any components



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Fig. Fig. 3: Always discard the old gasket

To install:
  1. Install a new gasket. Install the manifold and tighten the bolts to 18 ft. lbs. (25 Nm).
  2.  
  3. Connect the EGR valve to the exhaust manifold.
  4.  
  5. Plug in all electrical connectors.
  6.  
  7. Install the auxiliary air regulator with a new gasket.
  8.  
  9. Connect all vacuum and emission control hoses.
  10.  
  11. Connect the coolant hoses.
  12.  
  13. Install the cold start valve with a new gasket. If applicable, install the fuel injectors using new injector O-ring seals.
  14.  
  15. Connect and adjust the accelerator cable.
  16.  
  17. Fill the cooling system and connect the air intake duct to the throttle body.
  18.  

Digifant II Engines
  1. Disconnect the negative battery cable and remove the air duct from the throttle body.
  2.  
  3. Disconnect the accelerator cable and the wiring from the throttle switches.
  4.  
  5. Remove the idle stabilizer valve and disconnect the wiring from the fuel injector harness. Disconnect the fuel supply and return lines.
  6.  
  7. Remove the 2 bolts to remove the fuel rail and injectors as an assembly.
  8.  
  9. Label and disconnect the vacuum hoses and any remaining wiring as required.
  10.  
  11. Remove the bolts and remove the manifold from the cylinder head.
  12.  

To install:
  1. Use a new gasket and fit the manifold into place. Torque the bolts to 18 ft. lbs. (25 Nm).
  2.  
  3. Install the fuel injector assembly.
  4.  
  5. Connect fuel system hoses and vacuum lines.
  6.  
  7. Connect the wiring and throttle cable. Install the air duct and battery.
  8.  
  9. Run the engine to check idle speed and ignition timing.
  10.  

16-Valve Engines

See Figure 4

  1. Disconnect the negative battery cable and remove the air duct from the throttle body.
  2.  
  3. Disconnect the accelerator cable and the wiring from the throttle switches. Disconnect any vacuum lines at the throttle body.
  4.  
  5. Remove the idle stabilizer valve and disconnect the spark plug wires. On California models, disconnect the vacuum line and wiring from the EGR valve.
  6.  
  7. Remove the bolts to remove the upper intake manifold.
  8.  



Click image to see an enlarged view

Fig. Fig. 4: The intake manifold on 16-valve engines consists of an upper and lower portion

  1. To remove the lower intake manifold, pull the injectors straight out and put caps on the tips to protect them. Do not disconnect the lines.
  2.  
  3. Remove the nuts and remove the manifold.
  4.  

To install:
  1. Use a new gasket and fit the manifold into place. Torque the bolts to 18 ft. lbs. (25 Nm). Install the fuel injectors with new O-ring seals.
  2.  
  3. Use a new gasket and install the upper intake manifold. Torque the bolts to 15 ft. lbs. (20 Nm).
  4.  
  5. Connect the wiring and vacuum lines.
  6.  
  7. Install the idle stabilizer valve.
  8.  
  9. Connect the throttle cable. Install the air duct and battery.
  10.  
  11. Run the engine to check idle speed and ignition timing.
  12.  

Diesel Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system.
  4.  
  5. Disconnect the hose that runs between the air duct and the turbocharger (turbo-diesel only).
  6.  
  7. Remove the air cleaner.
  8.  
  9. Disconnect and plug all lines coming from the brake booster vacuum pump and remove the pump.
  10.  
  11. Disconnect the PCV line.
  12.  
  13. Disconnect and remove the blow-off valve and then disconnect the hose which runs from the intake manifold to the turbocharger (turbo-diesel only).
  14.  
  15. Remove the intake manifold from the engine. Clean the intake manifold gasket mating surfaces thoroughly. Make sure that all traces of the old gasket material are removed. Inspect the intake manifold for cracks and the gasket surfaces for warpage. If the manifold is damaged, replace it.
  16.  

To install:
  1. Install the manifold onto the engine with a new gasket. Tighten the bolts from the center towards the ends to 18 ft. lbs. (25 Nm).
  2.  
  3. Connect the intake manifold-to-turbocharger hose (turbo-diesels only). Install the blow-off valve.
  4.  
  5. Connect the PCV line.
  6.  
  7. Install the brake booster vacuum pump and connect the vacuum lines.
  8.  
  9. Install the air cleaner.
  10.  
  11. On turbo diesel engines, connect the air duct-to-turbocharger hose.
  12.  
  13. Fill the cooling system.
  14.  
  15. Connect the negative battery cable.
  16.  

 
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