Engine Knock and/or Rattle Noise, at Normal Operating Temp, that is More Pronounced on a Low Load Deceleration, at Idle and/or Under Light Load Conditions. Saturn Saturn 1994

For 1990-2009 cars

# Engine Knock and/or Rattle Noise, at Normal Operating Temp, that is More Pronounced on a Low Load Deceleration, at Idle and/or Under Light Load Conditions

Subject: | Engine Knock and/or Rattle Noise, at Normal Operating Temperature, that is More Pronounced on a Low Load Deceleration, at Idle and/or Under Light Load Conditions with Engine. (Replace Connecting Rod Assembly and Position Pin Retailers). This bulletin is being revised to include all 1995 Saturns by removing the VIN breakpoint that was under "Models Affected." This bulletin supercedes bulletin 94-T-48, which should be discarded.

Models: | 1994 and 1995 Saturns

### Condition

Some customers may comment about an engine knock and/or rattle noise from the engine that is more pronounced on a low load deceleration, at idle and/or under light load conditions (approximately 1600 rpm) with engine at normal operating temperature.

### Cause

This may be caused by a clearance condition between the piston pin and the connecting rod bushing.

### Correction

Perform the following procedure to correct the concern.

### Procedure:

1. Start engine and allow it to run until normal operating temperature of 97°C (207° F) is reached.
2. Bring engine speed up to 2000 rpm and allow engine to return to idle. Perform this step several times and listen for a knocking or rattle noise coming from the engine as the engine rpm returns to idle.
3. If a knocking or rattle noise is heard coming from the engine as the engine returns to idle:

• | While engine is running, disconnect each spark plug wire, one spark wire at a time, and note any change in engine noise. The engine noise should change when the affected cylinder's spark plug wire is disconnected.

| Important: Engine noise (knocking and rattling) reduces when effected cylinder's spark plug wire is disconnected.

• | When it is determined which cylinder is affected, refer to the appropriate year Engine Mechanical Service Manual and replace the connecting rod assembly and both piston pin retainers for the affected cylinder. While replacing the connecting rod assembly and piston pins, inspect the piston, piston pin connecting rod bearings for damage. It is not necessary to replace the piston, piston pin or connecting rod bearing if they are not damaged.

| NOTE: If unable to locate cylinder causing the knocking or rattling noise or if the noise only changes pitch, replace all four connecting rod assemblies.

| NOTE: When installing the snap ring cone on 1995 vehicles, tool SA9405E must be used. This tool is not properly identified in the "Engine Block" section of the "1995 Engine/Fuel/Air Intake/Exhaust Service Manual."

### Parts Requirements

2100897 | Rod Asm - Conn
21006521 | Gasket Kit - Cylinder Head (SOHC0 - 1991 - 1994 Vehicles (When part is depleted from Saturn Service Parts, P/N21007332 can be used)
210047332 | Gasket Kit - Cylinder Head (SOHC) - 1995 Vehicles
21006524 | Gasket Kit - Cylinder Head (SOHC0 - 1991 - 1994 Vehicles (When part is depleted from Saturn Service Parts, P/N21007335 can be used)
21007335 | Gasket Kit - Cylinder (DOHC) - 1995 Vehicles
21000816 | Retainer - Pstn Pin

### Claim Information

To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System as follows:

Case Type | Description | Labor Operation Code
VW | Connecting Rod Replacement | J1308
NOTE: Refer to the appropriate Electronic Saturn Labor Tine Guide for the correct time.