Knocking sound

[Jin1976]

When I move my car from stop there is knocking sound coming up from either the front or behind (I'm not quite sure where it come from). Upon higher speed the noise dissapear. What could it be? FYI my car is a 93 auto. Thanks in advance.

 

[hlweyl]

Try having someone ride in the car with you to try an locate the direction the sound is coming from. So many things can "knock", it'd be easier to know front or back. Also, does the knock increase/decrease with engine rpm or wheel speed?

 

[nsxtasy]

If this is happening only at very slow speeds, you might also have your friend stand alongside the car while you drive it slowly, to see if he can locate where the sound is coming from that way.

 

[Jin1976]

Try having someone ride in the car with you to try an locate the direction the sound is coming from. So many things can "knock", it'd be easier to know front or back. Also, does the knock increase/decrease with engine rpm or wheel speed?

Only when I move the car slowly. If I'm moving at higher speed the sound dissapear. Does it have to do with the wheel bearing as I had lower the car before and now I have risen it up again to save my tire from wearing to fast.

 

[Jin1976]

If this is happening only at very slow speeds, you might also have your friend stand alongside the car while you drive it slowly, to see if he can locate where the sound is coming from that way.

It sounds like its coming from the back. I don't think it could be my drive shaft as it has been service recently (change the drive shaft boot and inspect the drive shaft for any abnormality).

 

[matteni]

Try seeing if you can isolate it on a slow road:

- Try to see if the sound changes / stops when an constant speed and you engage/disengage a gear

- In neutral you can turn the engine off (1 click) and see if the sound changes

- Windows up or down does the sound change

- AC / Climate controll on or off does the sound change

- Parked pressing on the bumper in a oscilating motion, can you reproduce it

Just some things you may or may not have thought of.

 

[Jin1976]

Thanks for the tip

- Try to see if the sound changes / stops when an constant speed and you engage/disengage a gear

On constant speed there is no sound. On engaging a gear I'm not very sure.

- In neutral you can turn the engine off (1 click) and see if the sound changes

I have not try that one yet. Is it safe to do that on the engine?

- Windows up or down does the sound change

My driver side of the window won't come down. I have not fixed the broken cable yet.

- AC / Climate controll on or off does the sound change

Switching off the climate control does not do the trick. The sound is still there.

- Parked pressing on the bumper in a oscilating motion, can you reproduce it

Can you elaborate more? I don't quite understand.

Thanks in advance. I will take your advise.