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IMPORTPRO
IMPORTPRO, Mechanic
Category: Car
Satisfied Customers: 86
Experience:  10 YEARS FULL TIME MECHANICS IN IMPORT AUTOS,FROM MINOR TUNE-UPS TO MAJOR ENGINE AND TRANS REBUILDS
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My Mazda Rx8 makes a rattling noise under the hood in the morning

Resolved Question:

My Mazda Rx8 makes a rattling noise under the hood in the morning when the engine is cold. The noise is most pronounced in the inside of the car. As the day and engine get warmer the noise disappears until night-time when itget cold again. Please help.
Submitted: 7 years ago.
Category: Car
Expert:  IMPORTPRO replied 7 years ago.
I HAVE RUN INTO THIS PROBLEM SEVERAL TIMES I HAVE CONTACTED MAZDA,THEY INDICATE THEY ARE WORKING ON THIS ISSUE ITS CALLED SPARK KNOCK AND ITS COMMON ON THE ROTARY ONCE THEY HAVE A FEW MILES ON THEM,DONT THROW IT IN THE DUMPSTER YET.I AM CHECKING THE SERVICE BULLETIN FOR THIS ISSUE
Customer: replied 7 years ago.
I have been given this answer plenty of times by Mazda and their dealership. It also appears on one of the SB's posted by the Rx8 club. Your answer is not new therefore unnacceptable. How is it possible that a major Ford subsidary cannot find a fix for this seemingly simple problem? Just because they gave it a name does not mean the car is safe to drive nor that they have found a solution. Is there a possible backyard mechanic's fix?
Expert:  IMPORTPRO replied 7 years ago.

I HAVE DELT WITH THIS ISSUE MANY TIMES SIR,AND WITH ALL DUE RESPECT,A BACKYARD FIX AND A TABELOID WORTHY DESIGN FLAW DO NOT GO HAND IN HAND ,I DO HAVE THE" FIX" BUT ITS NOT A CHAIN AND TREE,IT IS A SLIGHTLY REDESIGNED KNOCK SENSOR THAT CONTINUALLY MANTAINS RETARDATION OF THE TIMINGTO REDUCE CARBON BUILD-UP IN THE CYLINDER VENTURI,HENCE RETAINING THE FACTORY DEFAULT DISPLACMENT.MAZDA HAS HAD TROUBLE WITH THIS THRU THE YEARS ,WITH OTHER ENGINES ALSO ,THEY WOULD IN FACT BENEFIT FROM LOOKING OVER THE SHOULDER

OF A HONDA ,NISSAN,TOYOTA ENGINEER FROM TIME TO TIME.

Customer: replied 7 years ago.
I have been told that red-lining the engine at least once daily would help get rid of the problem. Is this true? Would this procedure cause any damage to the engine or any of it's components and finally, does this really help reduce the engine noiseor is this just another one of Mazda's "Band-Aide" approach to fixing things?
Expert:  IMPORTPRO replied 7 years ago.

YES ACTUALLY IT CAN CLEAN UP CARBON BUILD UP,ALTHO THE THOUGHT IS REPULSIVE FOR MANY OWNERS,IT WILL NOT CAUSE DAMAGE BECAUSE ROTARYS THRIVE ON HIGH RPMS BUT IT WILL SLIGHTLY SHORTEN THE ENGINES LIFE SPAN,CONTRADICTING?,NO I MEAN IN TERMS OF WEAR,MORE REVS MEAN MORE WEAR.KEEP MAZDAS RECOMMENDED OIL IN IT. AND IT WILL

BE FINE AND YES IT IS A 'BAND-AIDE'.

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