Honda Pilot: A/C System Noise Check

Honda Pilot 2016-2022 (YF5/YF6) Service Manual / Remove, Install, Replace, Check info / A/C System Noise Check

Check

CAUTION

Air conditioning refrigerant or lubricant vapor can irritate your eyes, nose, or throat.
Be careful when connecting service equipment.
Do not breathe refrigerant or vapor.

The A/C system noise check will help you determine the source of abnormal A/C system noise.

NOTE:

If an accidental system discharge occurs, ventilate the work area before resuming service.
Additional health and safety information may be obtained from the refrigerant and lubricant manufacturers.
Identify the conditions when the noise occurs. The weather, the vehicle speed, the vehicle being in gear or in neutral, the engine temperature, or other conditions may be factors in determining the noise source.
Do the A/C system inspection, and correct any problems found prior to diagnosing abnormal noises.
Abnormal A/C noises can be misleading. For example, a sound similar to a failed bearing may be caused by loose fasteners or a faulty A/C compressor clutch assembly.

1. Other System - Noise Check

Turn the vehicle to the OFF (LOCK) mode, and check the following. Correct any problems found.
- Drive belt
  - Excessive wear
  - Oil contamination
  - Improper belt routing
- Faulty belt tensioner
- Air inlet grille (in the cowl cover) for debris
Start the engine, run the A/C system, and check if the noise is coming from the following. Repair or replace any faulty components.
- Drive belt
- Belt tensioner
- Any of the pulleys

2. A/C System (Cabin) - Noise Check

Cycle the HVAC system through all blower speeds and all air distribution modes, and check for unusual noises and excessive vibration. If noise and/or vibration are present, do the following checks.
NOTE: During this inspection, close the doors and windows, and do not start the engine.

Check for	Result	Also Check for
Conditions when the noise occurs	The noise or vibration occurs only in a specific mode or setting.	Check the operation of the air mix control motor, door, and linkage. Check the operation of the mode control motor, door, and linkage. Check the operation of the recirculation control motor, door, and linkage.
Conditions when the noise occurs	There is a squeaking or chirping noise, but no unusual vibration.	Replace the blower motor.
Foreign material in the blower motor and fan	Foreign material (leaves or twigs, for example) is present.	Remove it, and recheck for noise.
Foreign material in the blower motor and fan	No foreign material (leaves or twigs, for example) is present.	Remove the blower motor, and check these items below. Replace the blower motor if any problems are present. Damage on the fan blades Tightness of the fan retainer Fan alignment on the blower motor shaft

3. A/C System (Engine room) - Noise Check

Select a quiet area for testing.
Apply the parking brake.
Shift the vehicle in Neutral.
Start the engine.
Set the vehicle to the following items:
- Temperature control: MAX COOL
- Mode control: VENT
- Fan control: minimum (but not OFF)
- A/C: ON

Switch the A/C compressor on and off several times to clearly identify the sound during A/C compressor operation. Listen to the noise while the A/C compressor clutch is engaged and disengaged. Probe the A/C system with a stethoscope to pinpoint the noise.
NOTE: If the noise does not change when the A/C compressor clutch engages or disengages, the noise may be caused by an engine-related component. Probe the engine area with a stethoscope to pinpoint the noise.
Listen for noises coming from the A/C lines, the A/C hoses, the A/C condenser, the evaporator, the receiver/dryer, or the expansion valve, and check these items:

Check for	Result	Also Check for
Noises caused by A/C components touching other components or the body	The noise is present	Reroute or insulate the A/C component(s) as needed, and recheck for noise.
Loose, damaged or excessively worn A/C components or mounting hardware	Loose, damaged or excessively worn item is present	Repair or replace the faulty component(s) or hardware, and recheck for noise.
A moaning noise coming from the suction pipe and suction hose	A moaning noise is present	Check the system refrigerant charge. If the refrigerant charge is OK, replace the receiver/dryer.
A whistling or hissing noise from the expansion valve	A whistling or hissing noise is present	Evacuate the system for 3 hours, then recheck. If the noise is still present, replace the expansion valve.

Check for	Result	Also Check for
The A/C compressor clutch engages without slipping when the A/C is switched on.	Does slip	Replace the A/C compressor clutch. Replace the A/C compressor also if there is a leak from the shaft seal.
	Does not engage	Troubleshoot the A/C compressor clutch circuit.
The A/C compressor clutch disengages when the A/C is switched off.	Does not disengage	Do the A/C compressor clutch check. If the A/C compressor clutch is OK, replace the A/C compressor.
The A/C compressor clutch cycles on/off normally.	Rapid on/off cycle	Do the refrigerant leak check. If the refrigerant charge is OK, and there are no leaks, troubleshoot the A/C compressor clutch circuit.

Listen with a stethoscope for noises coming from the A/C compressor, and check these items:

Check for	Result	Also Check for
The noise changes when the A/C compressor clutch disengages (off).	Does not change	Check for the noise coming from the engine- related components.
The A/C system operating pressures are normal.	Abnormal	Troubleshoot the problem using the pressure test table in the A/C system test. Correct the pressure-related problem(s), and recheck for noise.
The A/C compressor hose connections and fasteners are in good condition.	Loose, damaged, or excessively worn.	Repair or replace the faulty component(s) or hardware, and recheck for noise.
	In good condition	Replace the A/C compressor.

Honda Pilot 2016-2022 (YF5/YF6) Service Manual

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