What is that noise in my car?

This just happened last night and I won’t be able to reach a mechanic until next week, so I need your help. Specifically, if i keep driving it, will i ruin my car?

I own a 2002 nissan sentra se-r.

Okay, so i started getting this weird knocking noise that i believe is somewhere on the left side of the engine area, in front of the steering wheel. It is also causing rattling to occur. The only thing i notice is that when i accelerate or brake hard, It goes away. Though when i stop that, it immediately returns. It is loud enough to drive me nuts on my way to work and causes vibrations that music can’t hide.

I did look under my car and didn’t notice anything unusual. So my main concern is will driving ruin my car, and second, does this sound like something i could fix myself or can you pinpoint a part of the car for me to investigate.?

There are too many things this could be to be able to tell you with any precision.

If it tends to happen worse or mostly when you are turning I’d say maybe CV joints, which tend to knock (fairly gently) for quite some time before failing (if they ever do) and won’t do anything catastrophic when they do fail other than leave you at the side of the road waiting for a tow. Personally I’ve never come across CV joints that knock so loud they are annoying, and you don’t mention the knocking being related to turning, so I assume that it still knocks when driving straight. So probably not CV joints. Heck, your car may not even have CV joints, I’m not familiar with it.

However I can say this: broadly speaking, loud knocking that “music can’t hide” is caused by something (or things) loose hitting something else hard. The cessation on braking/acceleration could be because they cause the loose things to come under strain so they are not free to knock around.

The loose thing/s are very likely causing damage to themselve or other things. The loose thing/s (obviously) are not supposed to be loose. It/they may get looser, and it/they may fall off/out/apart.

This is very very unlikely to be a Good Thing. If you have no clue about mechanical things, I’d be getting someone to look at it before you drive anywhere much more.

You’ll probably have to take it in for this one. Where do you feel the vibrations? Is it a whole car thing, or can you feel it say, in the steering wheel, or any of the pedals? Stick shift (if it’s a manual), maybe? Can you describe the noise a little better?

A few other things that come to mind: loose wheel nuts, a loose component to the driver’s front suspension. You don’t want either of those to come totally away.

Another thought: is it rhythmical knocking in time with how fast the car is going (ie speeds up as the car speeds up) or in time with how fast the engine is revving, or does it get worse with rough road surfaces or is it just knocking in a random pattern with no relationship to anything?

CV joints don’t knock or rattle when they go bad, they whine.

Without further details as to exactly when it occurs, i’m going to go out on a limb and say it may be brake related. Maybe a pad that is half-stuck to the rotor and causing the vibration, which would explain why hard braking and hard acceleration temporarily alleviates the problem.

Let us know!

I’ve had two cars that had CV joints that knocked when they went bad. A pad that is half stuck to a rotor is not going to knock so bad it can’t be drowned out by the radio.

Only the other day I had my mystery noise repaired. It started out of nowhere and was a rattly/knocking at a certain point just before each gear change. I took it in and thge mechanic told me it was a rubber thing that stops the engine mount rattling. His advice - leave it until next tune, unless it starts driving you crazy. He gave me the part number and I waited until last week’s service. Hope you get off as lightly.

Does happen at an idle? If it does, pop your hood and take a look, that should get you much closer to your answer. Also, for some reason, the first thing that I thought of was a loose exhaust part, which depedning on where the loose part, certainly isn’t a big deal, and should cost very much to get fixed.

I vote for loose wheel. Have it looked at immediately.

The clarify, I meant the outer CV joints. If the inner ones do, I haven’t noticed a case of it yet.

In 30+ years of professional auto repair experience, I have never heard a CV joint whine. The only noise I have ever heard from a CV joint has been a repeated knocking or clicking, usually on a tight turn when applying power. I don’t recall seeing a failed inner joint, the outers always seem to wear out first.

Good call. I owe you a cookie. I got nervous, so I went to my mechanic as soon as it opened this morning. I had loose lug nuts. On top of that, there was a large accumulation of rust behind the hubcaps that they removed. Due to the the rythmic mechanical noise, i tihnk it was the rust that was hitting something.

Though I feel like a putz, spending $180 to have someone tighten my lug nuts. Thanks for the responses. i hope this info can help others with noisy cars.

Don’t feel so bad, I spent $60 once to have my gas cap tightend.