2002 Mazda 323 - Strange Hissing Noise

I have a Mazda 323, although mine is an 1988 Model with 190k miles, but I don't have any hissing/whining nose. Are you sure they did your bearings correctly that would be a likely culprit, why did they need to be replaced in the first place?

Do you hear the noise when you rev the engine with out the car rolling?

Their could be many causes of this noise, any idea what direction the sound is coming from, front rear left right?

My initial suspect was the bearings (perhaps incorrectly done as they were fitted recently). The mechanic detected same to have worn out, and the noise was audible enough to confirm his advice. The latest noise is somewaht similar but more irritating (considering the bearings were changed). When the car is idle no such noise, and from standstil until approaching 80km when it starts. I will get the bearings re-checked.

Front, left. I first suspected the "newly" installed bearings. I will do further checks as suggested by the CR4 family. Thanks to all at CR4. My apologies for sending this as guest ealier...I forgot to change settings on my new computer, now it is sorted out.

Is the hissing/whinning road noise? It could be poorly balanced tyres (happened to my Mazda SP20 around the same speed but I am running low profile ones). Something to get checked properly as the ride seemed fine but the balance was way, way out.

Have you rubbed your hand over the tires? An uneven tread pattern could cause noise as described.

Try rolling a window down on the driver's side, and driving next to something that can reflect the noise back to you. Try a fence, wall, or parked cars. Then try the passenger side.Once you have decided which side is louder, the possibilities are cut in half. Switch the loud side tires front to back and retest. I had an Oldsmobile that came with Uniroyal tires. Good tires, but they squirmed against the outer edge of the rim. At low speeds it was easy to hear the tires squeak.

Have you noticed gas mileage drop off when the noise arrived? you could have a restrictive exhaust system. They can generate a wheezing sound as they become restrictive to engine air flow.

If it is a wheel bearing, it will become louder as you load it more. When you turn the car, the outboard wheel will become more loaded. If the noise gets louder on right curves, the left bearings are bad. Louder on lefts? The right bearings need attention.

If the bearings were replaced, and all of the old contaminated grease was not removed, the metal particles will find their way into the new bearings, and ruin them. Good luck.

Were you aware of the same noise prior to the brake pad and bearings replacement?

The answer to this post is a big NO. The vehicle was bought second hand and seemed somehow abused by the previous owner (police agency)

It depends on what you mean by "hissing/whining noise". Many years ago I hunted for ages trying to locate a 'similar' noise that also cut-in at a given speed - it turned out to be the wind driving the electric cooling fan when the road speed was high enough! May be worth a try!

Hi All, Just a thought is this vehicle fitted with asymmetric tyres if so were they fitted after bearing replacement on the correct side (Are they rotating in the right direction)

One other thing to check is the ventilation exit, this is usually covered with a thin ish plastic material which when damaged can cause all manner of weired noises

Just a thought...

I had a 1991 Olds Silhouette that picked up a strange vibration around 60mph (100kph). Turned out it was the radio antenna vibrating and transmitting the vibration to other areas of the mini van. Clear tubing around the antenna cured that.

Hooker

Are you certain the noise is caused by a mechanical component and not by the wind around a leaking body gasket? The fact the noise is only apparent above 80km/hr (50 MPH) suggests the problem is not mechanical. I suggest you support the front of the car with jacks with the front wheels off the ground. Then accelerate the engine until the speedometer reaches 80 km/hr and listen for the source of the noise. It would be possible for someone to lie under the car and listen but you must be extremely careful and make certain the car is supported correctly and can not move.

Dennis Waller

Are you certain the noise is caused by a mechanical component and not by the wind around a leaking body gasket? The fact the noise is only apparent above 80km/hr (50 MPH) suggests the problem is not mechanical. I suggest you support the front of the car with jacks with the front wheels off the ground. Then accelerate the engine until the speedometer reaches 80 km/hr and listen for the source of the noise. It would be possible for someone to lie under the car and listen but you must be extremely careful and make certain the car is supported correctly and can not move.

Dennis Waller

I will try this experiment. It gives me much hope of detecting the problem. Thanks a lot.