Need help on diagnosing this noise on my 98 DX.

When driving normally, I get a metallic humming noise at around 40-45mph. The noise goes when I press down on the gas and the speed goes up, but as soon as I hit around 45mph, under 50mph, the noise comes back. Any suggestions on what it could be?

I'm using the stock steelies and I haven't really checked the condition of the rotors or brake pads since I bought it, but brake still feels ok. Will change rotors and pads pretty soon. But they don't make noise when I use the brakes, etc. So i'm thinking it might be something else.

Just background info... the car has 88K+ miles, stock suspension(still good, rebound and stuff is good), stock steelies with a/s tires, stock clutch, haven't changed timing belt and stuff but generally in good running condition. Most of the general maintenance on it has been done since I bought it, but still a work in progress.

Could it be the wheel bearings? Belts? Pads/rotors? It loud enough that I can hear it over the radio and seems to be louder with the A/C on at setting 2 at the least. i can still hear it with the A/C off so that's why I'm stumped. I thought it was a belt that was slipping or something.

any help would be appreciated.

 

My first guess would be a heat shield rattling. They're right under the center of the car so that's it especially if it seems like it's not coming from a partcular wheel.

 

If it was the heat shield, I don't think it would be speed dependent so try reving the engine in neutral. If the problem is still there, then the heat shield is rattling. You can just tie it down with some mechanic's wire. It was a common problem on some of the late 90s accords.

 

Hmmm... will look at it again. I actually took off the heatshield under the car, downpipe to midpipe connection. I still have the heatshield on the cat itself, but i got a clamp around it. What's weird with the noise is that it only seems to happen at 45mph at cruise speed. Like I won't ven press down on the gas and it does it. If i hit the gas and go above 50mph.. then it's gone.

The heatshields around the cat/downpipe is rusting pretty badly, but the humming noise doesn't sound like its a rattle, but a constant whirly humming type crap. Revving the engine on neutral doesn't make any rattling noise. Although the car itself is noisy with stuff being rusty and all. I even got some weird buzzing noise whenever I shift gears.. since installing some energy suspension shifter bushings. but i have a feeling that's either the motor mounts or the catback is moving around with the engine/trans.

But this humming sound boggles me cause it doesn't happen at any other speeds jsut at/around 45mph.

 

lol...i had the same probem. turns out, if you only have your antenna half way out. its makes the most annying humming sound around 45 mph. took me forever to figure it out. hopefully this helps.

 

you must be kidding. cause i do have the antenna halfway down since i got a car wash like 2 weeks ago. hahaha.. i will try it out and see what happens. kidding or not. hehe..

edit* - tried it... nope... i have a big feeling it might be my tires being really noisy. oh well.. maybe i should just concertrate on that rattles and stuff on the car. [8D]