Popping noise left and right intermittently in the undercarriage?

ROBIN BLACKBURN

MEMBER
2005 FORD FOCUS
4 CYL
2WD
MANUAL
111,000 MILES

The pop almost sounds like exhaust. Drivers side and passenger side, behind the seats, next to the car frame. It can happen anytime, even sitting still. Loud like a rubber mallet hitting metal. Never happens left and right at the same time. Scary. Sometimes it doesn't happen at all. Driving around town. Too afraid to freeway drive. Help!

3 Replies

JACOBANDNICKOLAS

MECHANIC
108,269 POSTS

Hi Robin,

Is the sound loud enough for you to record and upload for me to hear? Also, is there anything you do that seems to prompt it to happen? For example, if you apply the brakes or hit a bump, does it happen? I realize you indicated it happens even sitting still, which is really interesting.

I attached an exploded view of the rear suspension parts of this vehicle. Most of the parts there are mounted via rubber bushings. If one has collapsed or broken apart, it can cause a noise. Also, a broken coil spring can also cause the sound.

The idea that you mentioned the exhaust is also a possibility. If you move the tailpipe around, does it feel loose? If you move it, can you reproduce the sound?

Let me know.

Joe

See pic below.

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Thursday, August 18th, 2022 AT 8:12 PM

ROBIN BLACKBURN

MEMBER
2 POSTS

Thank you, Joe. I would not be able to record the noise. It is too unpredictable. If you can think of a large rubber mallet hitting the undercarriage with a single thump, or bang that's the closest description I can come up with. I will check the exhaust pipe today. As far as prompts that cause the thump, there seems to be no explanation, not turning, going over bumps, or braking, Acceleration or letting up on the gas pedal does not seem to cause the problem. Do you think it is safe to drive locally while trying to figure out what to do? Thanks for your time and help. Robin

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Friday, August 19th, 2022 AT 9:47 AM

JACOBANDNICKOLAS

MECHANIC
108,269 POSTS

Robin,

I would suggest checking the rear components I mentioned. As far as it being safe, that is really hard for me to answer without knowing what is wrong. I'm sorry I can't give you a concrete answer.

The idea that it is that loud makes me think there is a bushing that is bad, and something is moving. The only thing is you indicate it happens when it is sitting still. That takes me back to the exhaust hitting.

If you aren't comfortable checking the things I mentioned, you really should have it checked at a shop where they can lift the vehicle and inspect things.

Let me know if you can have that done. Also, feel free to let me know if you have questions or if I can help in any way.

Take care,

Joe

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Friday, August 19th, 2022 AT 10:34 PM