Chrysler RAM50/D50/Arrow 1979-1993 Repair Guide

Heated Air Intake System

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OPERATION



Some models are equipped with a temperature regulated air control valve in the air cleaner snorkel.

When The underhood air temperature is 41°F or lower, the air control valve allows preheated air to flow through the heat cowl of the exhaust manifold, via a flexible hose, to the air cleaner and into the carburetor.

When the underhood temperature is 108° or above, the air flow is directed through the air cleaner snorkel.

At intermediate temperatures, the carburetor intake air is a blend of the direct underhood and preheated air.

INSPECTION



System Inspection

See Figure 1

  1. Remove the air filter cover and air duct.
  2.  
  3. Run the engine at idle and check the air control valve condition. At 86°F (30°C) or less, the cold air side inlet should close. At 113°F (45°C) or more, the cold air side inlet should open.
  4.  

If necessary, apply compressed air to cool or apply hot air using a hair dryer, etc. to heat.



Click image to see an enlarged view

Fig. Fig. 1: A diagram of a common intake air temperature control system-2.0L and 2.6L engines

Air Control Valve See Figure 2

A vacuum pump capable of producing more than 10 in. Hg (33.8 kPa) of vacuum will be needed to perform this test.

  1. Remove the air filter.
  2.  
  3. Disconnect the vacuum hose from the air control valve and connect a hand vacuum pump to the valve nipple.
  4.  
  5. Apply a vacuum of 19.75 in. Hg (67 kPa) and check to make sure the vacuum holds steady and does not leak down.
  6.  
  7. Check the air control valve operation. With a vacuum of 2.85 in. Hg (9 kPa) or less the cold air side inlet opens. With a vacuum of 7.53 in. Hg (25 kPa) or more the cold air side inlet closes.
  8.  
  9. Connect the vacuum hose back to their original position.
  10.  



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Fig. Fig. 2: Use a hand vacuum pump to check the air control valve

Thermo Sensor See Figure 3

A vacuum pump capable of producing more than 10 in. Hg (33.8 kPa) of vacuum will be needed to perform this test.

  1. Connect a hand vacuum pump to the thermo sensor nipple and check air tightness. With the thermo sensor temperature at 86°F (30°C) or less the vacuum should not leak. With the thermo sensor temperature at 113°F (45°C) or more the vacuum should leak.
  2.  
  3. If any fault is found in the above checks, replace the air filter body.
  4.  



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Fig. Fig. 3: Using a vacuum pump, check to make sure the thermo sensor holds vacuum at 86°F (30°C) or less

REMOVAL and INSTALLATION
Air Control Valve

See Figures 4, 5 and 6

  1. Remove the vacuum line to the air control valve.
  2.  
  3. Remove the bolt for the air control valve retaining bracket, and bracket.
  4.  
  5. Lift out the control valve from inside the air cleaner housing and disconnect the linkage.
  6.  



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Fig. Fig. 4: Separate the vacuum line attached to the air control valve



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Fig. Fig. 5: Remove the mounting bolt and bracket retaining the control valve



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Fig. Fig. 6: Lift the control valve from the air cleaner housing and disconnect the linkage

To install:
  1. Place the control valve into the air cleaner housing attaching the linkage.
  2.  
  3. Attach the bracket with the retaining bolt and tighten.
  4.  
  5. Attach the vacuum line to the valve.
  6.  

 
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