Engine - Metallic Rattle Noise During Warm-Up
88nissan03Classification: EM88-009 Section: Engine Mechanical
Reference: TECHNICAL BULLETIN TS88-053
Models: 1986.5-1988 Truck (D21)
Date: March 25, 1988
METALLIC RATTLE NOISE FROM
OIL PUMP RELIEF VALVE DURING WARM-UP
APPLIED MODEL: 1986.5-1988 Truck with Z24i engine (2WD models only)
APPLIED VIN: Built before: 1N6ND16S_JC301387 JN6ND11S_JW001447
JN6ND12S_JW000125 August 11, 1987
JN6ND16S_JW000914
SERVICE INFORMATION
Some 1986.5 - 1988 2WD trucks equipped with the Z24i engine may exhibit a metallic rattle noise (similar to an exhaust heatshield rattle) from the engine oil pump area during the engine warm-up period. This noise is caused by the oil pump pressure relief valve oscillating against the pump housing. It is most noticeable during fast idle of 1200-2000 RPM and occurs about 30 seconds later, and will be gone after about 8 minutes of engine warm-up, when the engine oil temperature is almost 40~C.
To determine if the noise is from the oil pump relief valve:
1. Allow the vehicle to remain unstarted for a minimum of six (6) hours.
2. Start engine and let it idle.
3. When noise occurs, use a stethoscope (or equivalent), to verify if noise is being emitted from the engine oil pump.
4. As indicated below, the rattle noise should diminish as the engine warms up, and will be completely gone when the engine oil temperature reaches 40~C (i.e. after about 8 minutes of engine warm-up).
If the metallic rattle noise is verified to be coming from the oil pump, replace the engine oil strainer with the countermeasure oil strainer and bolt listed below.
If the engine noise does not fit this description or cannot be verified to be from the oil pump area, DO NOT install the countermeasure parts. Call the FIXS Hotline for further information and assistance.