A/c-Heater System - Automatic: NVH Nissan Pathfinder II

NOISE

1. If noise is being produced by blower motor, check for noise in all modes and temperature settings. If noise is constant, check blower motor for foreign particles. Check blower motor and fan for wear. Check air discharge ducts for obstructions, foreign materials or air leakage.
2. If noise is being produced by compressor, check compressor clutch, clutch pulley and idler pulley. Check disc-to-pulley clearance. Clearance should be 0.012-0.024" (0.3-0.6 mm). Check for correct amount of refrigerant oil in compressor. If all components are okay, replace compressor and accumulator.
3. If noise is being produced by expansion valve, replace expansion valve. If noise is being produced by refrigerant lines, check if refrigerant lines are properly affixed. If lines are affixed properly and are still producing noise, install rubber insulation between refrigerant line and vehicle body.
4. If noise is being produced by A/C compressor belt, check for loose or worn belt. Adjust or replace belt as necessary. Also, check for proper A/C compressor belt pulley alignment.