Miata Technical Service Bulletin

Category Applicable Model(s) Subject
Bulletin No. 003/90
Issued 4/23/90
F 1990 MX-5 Miata Exhaust Manifold Heat Insulator Bracket Breakage

1990 - Vehicles with a VIN of JM1NA351*L0100001 through JM1NA351*L099999


If you encounter a customer complaint regarding a rattling noise from the engine compartment, it may be the result of a broken exhaust manifold insulator bracket on the No. 1 cylinder side. When you find a broken bracket, replace it with the replacement bracket shown on page 2 of 2.

VIN of Production Change

The thickness of the production bracket has been increased since the July, 1989 production.

JM1NA****L0113830 - July 14, 1989

Parts Information

Part Number Description
B6Y0 13 468A Exhaust Manifold Insulator Bracket

Service part only.

Repair Procedure

  1. Get a new bracket (P/N B6Y) 13 468A).
  2. Remove the exhaust manifold insulator.
  3. Remove the faulty bracket from the exhaust manifold. Carefully remove the old bracket where necesary with a suitable tool. Inspect the manifold for holes when finished.
  4. Install the new bracket using the upper and lower nuts which fix the exhaust manifold at the No. 1 cylinder (refer to the illustration.)
    Tightening Torque of Nuts: 28 - 34 in-lb (3.9 - 4.7 m-kg)
  5. Install the insulator.
    Tightening Torque: 69 - 95 in-lb (0.8 - 1.1 m-kg)

Warranty Information

Warranty Type Code: A
Customer Comment Code: 82
Damage Code: 9A
Part No. of Main Cause B6Y0 13 468A
Quantity: 1
Operation No. XX0359-R-X
Labor Hour: 0.4 Hr.

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