Very light hammering sound comes from engine bay Honda civic 2007 97K

General Discussion
1

Hi All,

I have Honda Civic 2007 model 97km odometer reading automatic. I bought it used 2 months back.

I realized an unusual sound from engine bay (mild hammering sound when in gears) when engine is warm (not in neutral) and only noticeable when it is in closed places like a parking garage.

The sound will not be noticiable if I start car in the morning and only noticeable after drive it for few kilometers.

My mechanic told me that it is from “begining bearing” and when engine is cold then due to high viscocity the sound will be not noticeable and when the car runs the viscocity of the oil will change (lighter) then the sound is noticeable.

I am attaching two mp3 sound files which I have recorde in my parking garage. When I Shift to gears the sound appears and when I shift to neutral the sound vanished off.

Pls bear with the sound quality.

[https://www.dropbox.com/s/8f8f67b9v4t0w2s/Mild%20hamering%20sound1.mp3?dl=0](http://Mild Hearing Sound 1)

[https://www.dropbox.com/s/6kocm43y0coinpz/Mild%20hamering%20sound2.mp3?dl=0](http://Mild Hearing Sound 2)


Moreover, My mechanic said that I need to change the oil more frequently to not increase this sound. Otherwise, this is not impacting any other parts or engine. and this could be due to sudden throttle (i.e waiting on signal and suddenly raved the engine when it turns green).

Thanks,
Abhi

2

Not sure what that means. Might he have said “spinning bearing”?

3

I think your mechanic is on the right track concerning oil and oil changes. Be sure to use the viscosity specified for your car, should be on the oil fill cap, numbers like 5W-20.
You may need a valve adjust too, consult your mechanic about this.

4

Sounds to me like a worn rod bearing.
Likely the previous owner neglected oil changes.
I’d try using 5W-30 or 5W-40 oil to reduce the sound.

5

It’s puzzling that the sound occurs in gear but not in neutral.

I check my 1999 Civic’s valve clearances every 35,000 miles or so, along with spark plug changes. Each time some have drifted out of spec, so I adjust them, and each time the engine runs a little better afterward. The manual that came with my car does not call for this work unless the valve train becomes noisy. If the 2007 uses a timing belt, that, too, or its tensioner, may be needing attention.

6

… or, perhaps the mechanic was talking about the Pilot Bearing.

7

OP states it is an automatic, but it might be transmission related since the noise is not present in neutral.
Transmission fluid service might help.

8

Couldn’t play the audio, but could be what’s called piston slap. It’s caused by bore wearing too large. Putting it in gear Will increase engine load enough to cause the piston skirt to slap the sides of the bore. When engine warms, rings and skirt expand, and knocking may stop.