Engine - Top End Noise

Bulletin No.: 008/93
Issued: 11/5/93
Revised: 12/17/93

Category
B

Applicable Model/s
See Below

Subject:
HLA NOISE

The revised portion of this bulletin is indicated by an asterisk (*). Replace the original with this revised copy.

APPLICABLE MODELS/VINS

323 (GTX, 4WD)

1988 - Vehicles with a VIN of JM1BF234*J0100001 through JM1BG234*J0199999
1989 - Vehicles with a VIN of JM1BF234*K0200001 through JM1BG234*K0299999

MIATA

1990 - Vehicles with a VIN of JM1NA351*L0100001 through JM1NA351*L0199999
1991 - Vehicles with a VIN of JM1NA351*M0100001 through JM1NA351*M0299999
1992 - Vehicles with a VIN of JM1NA351*N0300001 through JM1NA351*N0399999
1993 - Vehicles with a VIN of JM1NA351*P0400001 through JM1NA351*P0423272

Protege (with DOHC)

1990 - Vehicles with a VIN of JM1BG224*L0100001 through JM1BG234*L0199999
1991 - Vehicles with a VIN of JM1BG224*M0200001 through JM1BG234*M0399999
1992 - Vehicles with a VIN of JM1BG224*N0400001 through JM1BG234*N0599999
1993 - Vehicles with a VIN of JM1BG224*P0600001 through JM1BG234*P0654718

NOTE:
The asterisk (*) in the VIN range can be any number (0 through 9) or "X".

DESCRIPTION

A noise at the top of the engine that occurs several times faster than crank shaft rotation may be caused by restricted oil flow through the hydraulic lash adjusters (HLA's).
The noise is most common after cold engine starts or when returning to idle after highway driving (high speed). To correct the noise condition, HLA's have been modified to increase oil circulation.
If a customer complains of HLA noise and the vehicle is within the VIN range above, follow the repair procedure in this bulletin.

NOTE:
This bulletin replaces the instructions in Service Bulletin 011/91, Category B. Refer to page 7 of the 1991 Service Bulletin Book (P/N 9999 95 008N 92) for a copy of the 011/91 bulletin.
If the HLA's require replacement, inform the customer that maintaining regular oil changes according to the scheduled maintenance will help prevent this noise from returning.

REPAIR PROCEDURES *





1. Check engine oil level. If the level is below "L", add oil.

2. Start the engine and verify the HLA noise. If the noise is not present, change the engine oil and inform the customer that regular oil changes will help prevent the noise from returning. If the noise is present, proceed to step 3.

3. If noise is present, increase the RPM to 2000 - 3000 for 2 minutes. Return to idle and check again for HLA noise. If noise is sill present, increase the RPM to 2000 - 3000 for 10 minutes. Return to idle and check again for HLA noise. If noise is still present, proceed to step 4.

4. Perform engine carbon cleaning as described in Service Bulletin Category B, # 004/93.

5. If noise is still present, remove the rocker arm assembly covers and check for excessive clearance between the cam shaft and the HLA.

NOTE:
HLA must not be in a compressed position. Turn the cam slowly to avoid air entering the HLA.

6. If 0.15 mm or more can be inserted between the cam shaft and the HLA, replace the HLA.





PARTS INFORMATION

WARRANTY INFORMATION (Applies To Vehicles Covered Under Normal Warranty)

Warranty Type: A
Customer Comment Code: 82
Damage Code: 99
Part Number Main Cause: KL01 12 101B
Quantity: As Necessary
Operation Number / Labor Hours: B04010BRX / 3.0Hrs. (MX5), B0410CRX / 2.8Hrs. (Protege

NOTE:
Refer to Service Bulletin Cat. B # 004/93 for warranty information on carbon cleaning and oil change.