Hey guys and gals, I have an interesting issue that I'm not sure if it's something bad or just normal. When driving while accelerating or maintaining a constant speed, there is a harmonic noise. At lower speeds, it's a lower frequency and at higher speeds it's a higher frequency, kind of like the sounds you get from tuning forks. Now it doesn't happen when I decelerate or if I am in neutral, only when I am pushing down on the throttle. It isn't dependant on the gear I am in, meaing that at 66 mph, it's the same frequency in 5th as it is in 4th gear. So it's dependant on something spinning I'm assuming. I haven't lost power and haven't had any other problems. Also, at certian speeds like 66mph and I think around 45mph, the noise gets a lot louder, as if it's hit a certain sine wave or something (trying to rememeber high school science)

Notes on car: Royal Purple 5w20 oil, Royal Purple transmission fluid, K&N filter only, and Megan catback exhaust which shouldn't matter I don't think.

Any thoughts or anyone notice this before?

 

We just had something somewhat similar happen on our 02 Honda CRV however it was only under deceleration. We found out it was nothing more than tire noise, but since the tires were cupping, it would somehow make some sort of resonant frequency and white and whistle because of it. Not saying this is what it is on your car, but just throwing something out there.

 

Interesting, but yeah I wouldn't think it would be the tires since the noise actually stops when letting off of the throttle. But thank you for the info!!

 

True, true, but the thing with the CRV was that the noise wasn't there when ON the throttle, only when off, so although the symptoms seem reversed, they may be somehow related... curious to see what others have to say.

 

Alternator noise?

 

goingcarcrazy: Yeah, as soon as I replied, I thought about that too.

Chrislilja: Do you think it would be the alternator itself or the pulley that would make the noise?

 

Do you have any after market audio (amplifier could cause it) or aftermarket pulley...?

 

No aftermarket pullies, and only one little alpine amp that's maybe 250 watt.

 

i have this same proboblem. i took it to the dealer and they said it was my tires. i thought it was my bearings at first.
can you hear it coming from a specific location on your car with all the windows up?

 

Yeah, I drive an hour to get to work and I always have them up. It's definately coming from the front of the car as far as I can tell. I was thinking it would be a bearing or something also. I guess I'll check the tire pressure since we have had some pretty big temperature changes lately. Strange how the tires would make a noise like that!

 

well if the are "scuffed" or have uneven tread wear this can happen. try rotating for tires from front to back and see if the sounds moves.

 

gotcha, i'll try rotating them probably next weekend if I don't have time this weekend since it's oil change time anyway and I can do both at one time. thanks for the suggestion! I'll post up results after I get to it.

anyone else have other ideas, feel free to throw them at me....well not literally.

 

If it's vehicle speed dependent it's definitely not your alternator.

When you rotate the tires try cross rotating them [R front to L rear and vice versa]. This will change the direction the tire spins in, and might help identify if it is the tires.

 

^unless your tires are directional!!!!!! if they are meant to rotate in one direction DO NOT CROSS ROTATE!!

I never take for granted how much ppl know about cars. You are much much safer just rotating from front to back on the same side!

 

You don't want to leave it that way permanently, but you'll be fine temporarily rotating the other way.