Engine - Excessive Induction Noise

GMC NUMBER: 87-T-26

SECTION: 6C - Engine Fuel

DATE: January, 1987

SUBJECT: INDUCTION NOISE

MODELS: 1987 S/T TRUCK WITH 2.5L (VIN CODE E) L4 ENGINE

Figure No. 1 - Air Cleaner Assembly:

Some 1987 S/T trucks with 2.5L L4 engines may exhibit unsatisfactory levels of engine induction noise due to overtorqued wing nuts on the air cleaner cover. This condition causes the air cleaner cover to become distorted, leaving a small gap between the cover and the air filter element and could also cause the air filter element to become crushed (See Figure No. 1).

If this condition is encountered, remove the air cleaner cover and check for damage. Repair the cover if required. Check the air filter element for signs of distortion or crushing (See Figure No. 1). Replace the air filter element if damaged. Reinstall the air cleaner cover and wing nuts. Torque wing nuts to 1.6 - 2.4 N-m (14-21 lb.in).