Protegé FAQ - TSB MT000001256

ENGINE NOISE FROM CARBON KNOCK

Applicable Models

Model	Starting S/N	Ending S/N
1990 323	L0100001	R0757199
1990 PROTEGE	L0100001	R0757199
1991 323	L0100001	R0757199
1991 PROTEGE	L0100001	R0757199
1992 323	L0100001	R0757199
1992 PROTEGE	L0100001	R0757199
1993 323	L0100001	R0757199
1993 PROTEGE	L0100001	R0757199
1994 323	L0100001	R0757199
1994 PROTEGE	L0100001	R0757199

0001256 Dealer Repair Information

A knocking noise when first starting a cold engine may be mistaken for  
HLA noise and may gradually decrease as the engine temperature rises.   
                                                                        
Carbon Flush the engine using the procedures outlined in service        
bulletin Category B, 004/93.                                            
                                                                        
If the carbon knocking noise returns, install modified pistons developed
                                                                        
to increase the cylinder head to piston top clearance an additional     
1.3mm.  PARTS INFORMATION:                                              
                                                                        
                       P/N                DESC.                         
                   BPY1-11-SA0A       Piston for 1.8l DOHC              
                                                                        
                   BPY0-11-SA0A       Piston for 1.8l SOHC