F 250 4WD Pickup V8-7.3L DSL Turbo VIN K (1994)
Evaporator Case: All Technical Service Bulletins
A/C Plenum - Whistling Noise With Fan ON
Article No.
94-23-14
11/14/94
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NOISE - "WHISTLING" NOISE COMING FROM PLENUM AREA WHEN FAN IS ON
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WINDNOISE - COMING FROM PLENUM AREA WHEN BLOWER IS ON
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AIR CONDITIONING - "WHISTLING" NOISE COMING FROM PLENUM WHEN FAN IS ON
LIGHT TRUCK:
1994 BRONCO, F-150-350 SERIES, F-47
ISSUE:
Some vehicles may experience a "whistling" noise coming from the plenum area. This noise may be most noticeable when the blower motor is on the
"HI" or "MED-Hi" positions. Five locations on the plenum have been identified as likely areas where noise conditions may develop. They are as follows:
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The bottom heater core cover locating pins.
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Tooling hole region.
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Inboard upper stud region.
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The region above the temperature door at the pivot, inside the plenum.
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Heater core cover outer diameter, most likely the bottom, right side, middle and left side middle.
ACTION:
Diagnose the correct location of the windnoise and repair according to the following service procedure.
NOTE:
IT IS CRITICAL THAT A PROPER DIAGNOSIS BE PERFORMED SO THAT THE SOURCES OF OTHER NOISES (I.E., BODY WIND,
REGISTERS, DUCTS, ETC.) ARE ELIMINATED AND THE PLENUM IS PINPOINTED AS THE CONCERN AREA.
