MX-5 Miata L4-1597cc 1.6L DOHC (1992)
Rocker Arm Assembly: Customer Interest
Hydraulic Lash Adjusters - Noisy
Bulletin No.: 002/94
Issued: 1/13/94
Revised: 2/11/94
Category: B
Applicable Model/s
See Below
Subject
HLA NOISE
NOTE:
The revised section of this bulletin is indicated by an asterisk (*). Replace the original bulletin with this revised copy.
APPLICABLE MODELS/VINS
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 still 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.
NOTE:
Monitor engine coolant temperature to avoid overheating during step 3.
4.
Perform engine carbon cleaning as described in Service Bulletin Category B, # 004/93.
