Miata Technical Service Bulletin

Category Applicable Model(s) Subject
Bulletin No. 011/91
Issued 11/22/91
B (See Below) Hydraulic Lash Adjuster Noise


Some models (1988-'89 323 GTX 4WD, 1990-'91 MX-5 Miata and 1990-'91 Protege with DOHC 1.8L engine) may develop hydraulic lash adjuster (HLA) noise during cold start and when returning to idle after freeway driving. This is caused by restricted oil flow through the HLA.

HLA's with an increased oil passage are available as a service part for vehicles experiencing HLA noise. There has been no change in the design of HLA's used in production. Inspect and replace bad HLA's according to procedures in your Workshop Manual.

Please instruct your customers to observe scheduled maintenance intervals. Inadequate amount of oil, incorrect oil grade (weight) or oil deterioration may cause this problem.

Parts Information

Part Number Description Applicable Model
B6Y1 12 101 Hydraulic Lash Adjuster 1988-'89 GTX 4WD
1990-'91 MX-5
1990-'91 Protege DOHC 1.8L

Warranty Information

Warranty Type Code: A
Customer Comment Code: 82
Damage Code: 92
Part No. Of Main Cause B6Y1 12 101
Quantity: Maximum of 16
Operation No./ Labor Hour: B0410BRX/2.6 Hrs.
B0410BRJ / 2.8 Hrs. (DOHC engine only)

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