Weird noise..

[Two Fowty]

It happens when I am going anywhere from 18-20 mph.. or 1800-2100 rpms roughly.. I can be in 2nd, or in neutral coasting, or anything, it just happens..

The noise is a thumping noise, sounds like a really fast heartbeat almost, and it will fade in and become audible at 18 mph and then fade out at 20.. Also, for a while, the range at which it occurred at dropped down to 15-18mph, and now its back at 18-20.

I think it is coming from the passenger front of the car. I know for a fact it is in the front of the car though.

And it happens when I'm going straight, or turning, doesnt matter the direction of my car.

Any help will be very appreciated.
Modified by Two Fowty at 3:11 PM 5/24/2009

[E7-S14]

heat shield..one of the many..

thats most likely it.they get old, loose, and rust. then rattle.

[Two Fowty]

heat shield..one of the many..

thats most likely it.they get old, loose, and rust. then rattle.

if that were the case, wouldn't it rattle constantly, and not just at that certain range..

and btw, when it is in the middle of the ranges i told you, it is loudest, then it fades out either way.

[maj Andres]

Ebrake cables hitting your driveshaft? It's happening to me

[Two Fowty]

Ebrake cables hitting your driveshaft? It's happening to me

does yours make the sound only at a certain speed?

[maj Andres]

that noise actually just came back today. my cables chewed up down to the metal! it makes that sound when i'm accelerating, then goes away. I shift, accelerate, noise, goes away, etc... It comes and goes. Not saying this is your problem, but it might be a possibility. Have you recently removed your cables?

[zenkistic]

heat shield..one of the many..

thats most likely it.they get old, loose, and rust. then rattle.

I have the same "issue", next time I lift the car I will remove it the other piece as well. OP, try revving the car while on neutral. It may only happen for a specific range. For me it's like 25-35mph.

[Two Fowty]

i reved up my car and i hear a noise that starts at the same time the noise does when the car is moving, but this noise is a different noise. most likely connected.

what heat shield are you talking about?

my engine is just a ka

[S13Joe]

Heat shield is right on the header. Yours may have been removed, i removed mine because it was barely hanging on by anything. Does the sound come at idle as well? It may be the throwout bearing. Where is the sound coming from exactly. You need to be more specific, It could be alot of things.

[CSLAVE]

^ could also be the heat shield on your cat converter. If it a high pitched, thin metal, ringing noise then it could be that. Happened to my car at a certain RPM.

I put a clamp around mine just cause i didn't have a welder on hand.

[S13Joe]

Thats also true, I realized that after I posted. My heat shield on the cat was broken off and the top part was smacking up underneath me. Weird sound but it went away at a smoother speed. To be exact, I just removed a stock exhaust my shell about 2 weeks ago, the shield on the cat was intact before I pulled it out, its very weak.

[Wc240]

its hard to tell whats making a noise over the internet. the easiest way is gonna be to stick your head near the underside of the car, while someone revs it up. then just keep working closer to the noise. if you think it is one of the heat shields, grab it with a pair of pliers, with or without a rag, then rev it up. if the sound goes away, youve found it.

[Two Fowty]

It isnt at idle. I know my throwout bearing noise, and i hear that at idle, but nothing else. I dont have a heatshield on my headers, but i'll check the one on the cat today.

thanks guys

[kpodj61240]

this may be way out there but ill go for it. i had a noise every time i reved up my motor and when i let off it made a cha cha cha noise. i thought i was somthing internal. it would also do it with driving here it was my bottom alternator bolt. the nut some how came off. so i dont know. if u want just make sure all ur sh1t is not loose and chattering

[zenkistic]

^ could also be the heat shield on your cat converter. If it a high pitched, thin metal, ringing noise then it could be that. Happened to my car at a certain RPM.

I put a clamp around mine just cause i didn't have a welder on hand.

Yeap, the shield that is rattling in my case is the first shield of the exhaust system under the engine. I would say this is the exhaust manifold shield, but I may be wrong. Eitherways, I can see it hanging if I bend down and look next to my front left wheel. I initially thought it was a clutch thing, but it was only that shield. Hope that solves your problem OP.

edit: The noise maybe a little different in each case, because different metal mass resonates at different frequencies -> different sound.

[Two Fowty]

um. i did a small check on the heatshields on my exhaust stuff and its all pretty tight so i dont see much room to rattle there, and its not in the right area that im hearing the noise from. so any more ideas?

[Two Fowty]

i think it is actually the heat shield on the exhaust, is this needed? can i just yank it off and be done with it.

and just for clarification, this isnt the shield on the headers, its on the piping a bit further down from the headers.

[maj Andres]

You talking about the one that is underneath the car, above the cat? If it is, then yeah take it out, it's only on there with three small bolts. I took mine out before I steam cleaned the undercarriage of my 240sx.

[Two Fowty]

im a noob for saying this, but i dont even know.. i assume the down pipe, is the pipe coming down from the headers lol.. and the shield starts at the down pipe, then goes down and comes back about a foot or two on the exhaust, and then there isnt any more shielding.

ill just take it off.

[Two Fowty]

so i took off all my heat shielding on my cat, and guess what.. sound is still there.. i noticed my shifter shakes more than normal when i hear the noise, then it subsides once it stops. any ideas

[OutToWinPAHC]

Probably internal to the transmission. Could also be the shaft or the rear.

[Two Fowty]

so i did a little driving, and im not so sure its the clutch anymore. cause i thought the shifter was shaking when the noise happens.. but it just shakes throughout 2nd gear, and i held the shifter and felt it and it isnt shaking with the noise, and it is dead still when im coasting in neutral and i hear the noise. but it is right in the area of the shifter, or so i think.