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hey guys. so when I am running about 2700 or so rpms I get a weird knocking sound in the front end. it kinda sounds like a train noise or somthing. it only makes the noise at that exact rpms. could it be the belts flapping aroubd or somthing?

 
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Can you reproduce the noise in neutral? If so, try to precisely pinpoint the source of the noise.

 
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its very common, like a rattle sound. i get it all the time too around same rpms. i think its just valve noise cause when i rev it in N with the hood open, i can hear it coming from inside the engine.

 
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If it's a rattling sound, also check the exhaust heat shields.

 
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i have no heat shields at all

 
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While this rules out heat shield noise for you, the OP may not have deleted them from his Civic. Heat shields are a very common source of annoying noise for Civics.

 
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I tried bringing my car to 2700 rpms in neutral and there was no noise. mabe it only does it when theres load on the motor.

 
Rep Power: 228

Is it a metallic rattle or squeaking noise? If so, put the front end on stands and carefully inspect all of the exhaust heat shields for looseness or cracks.

When I had heat shield noise, it also only happened during acceleration around the rpm range you mention. Turned out to be a hairline crack near one of the shield attachment bolts.