A/C - Drone Noise at Idle

BULLETIN NUMBER:
AC92-002

SECTION:
HEATING & AIR CONDITIONING

DATE:
AUGUST 21, 1992

TITLE:
2VZ-FE IDLE DRONE WITH A/C "ON"

MODELS:
ES 250

ES 250's may exhibit an A/C drone noise at idle under the following operating conditions:

- Ambient temperatures above 75° F

- Air Conditioning System "ON"

- Transmission in "D" Range

- A/C Compressor operating in 100% mode

- Idle speed 800 - 1,100 RPM.

NOTE: Care must be taken not to confuse normal engine mechanical noise with this condition. Always confirm the condition using the operating conditions above.





To correct a customer complaint for the above condition, the kit shown in the illustration has been made available to decrease the drone noise.

INSTALLATION PROCEDURE:





Parts List

STEP 1:

A) Discharge the A/C system using an approved recycling station. Refer to your ES 250 Repair Manual for all necessary safeguards and specifications.

B) Replace the suction hose with the one provided in the kit.

STEP 2:

A) Loosen and remove the alternator adjusting bolt.

B) Loosen and remove the two bolts located at the front of the A/C compressor mounting bracket (BOLT 1).

C) Install the pulley bracket (BRACKET A) with the two new M10 x 7O mm bolts (BOLT A). Temporarily tighten these bolts.

D) Loosen and remove the upper compressor mounting bolt (BOLT 2).

E) Install the pulley bracket (BRACKET B) with the new M8 x 120 mm bolt (BOLT C). Temporarily tighten this bolt.





F) Loosen and remove the alternator mounting bracket bolt (BOLT 3).

G) Install the pulley bracket (BRACKET C) with the new M10 x 55 mm bolt (BOLT D). Temporarily tighten this bolt.

H) Join BRACKET B to BRACKET A with the two bolts supplied (BOLT E). Torque to: (M8 x 3O mm) 14 ft lbs (19 N.m)

I) Attach BRACKET C to BRACKET B with the bolt supplied (BOLT F). Torque to: (M6 x 25 mm) 14 ft lbs (19 N.m)

J) Torque all remaining bolts completely.

Bolt A (M10 x 70 mm) 27ft lbs (37 N.m)

Bolt C (M8 x 120 mm) 18 ft lbs (25 N.m)

Bolt D (M10 x 55 mm) 27 ft lbs (37 N.m)

H) Install the new M8 x 90 mm adjusting bolt (BOLT B) and adjust belt tension to specifications:

New Belt 175 ± 5 lbs

Old Belt 115 ± 20 lbs

STEP 3:

A) Evacuate the A/C system.

B) Charge the A/C system to specification:

600 - 750 g (1.32- 1.85 lbs)

C) Operate A/C system and perform a leak check.