Download 1999-00 Miata 1.8L Rattling Noise From Engine Service Manual – APPLICABLE MODEL(S)/VINS All 1999 Protege (1.6L) with VINs lower than JM1 BJ222* X0 140057. All 1999 – 2000 Miata with (1.8L) VINs lower than JM1 NB353* Y0 155947. DESCRIPTION A rattling noise may be heard from the engine when depressing the clutch or when revving the engine in neutral. In extreme cases, customers may experience noise at all times. This concern can be caused by improperly machined number 4 main cap of cylinder blocks which may result in premature wear of the thrust bearing. Customers having this concern should have their vehicle repaired using the following procedure REPAIR PROCEDURE 1. Verify customer concern. 2. Using a dial indicator, measure and record the crankshaft end play as shown (Protege). Rotate the crankshaft 180o, and again measure and record the crankshaft end play. – If end play is 0.3mm or more, proceed to STEP 3. – If end play is still less then 0.3mm, refer to the Work- shop Manual for further diagnostics. 3. Replace the applicable part per the Workshop Manual: • Protege – Short Engine • Miata – Partial Engine Note • Completely clean any parts that will be reused. 4. Verify the repair.