Noise in LGT

[__raj]

I found this video(not mine) on youtube and it sounds like our LGT 50-70MPH although not quite as loud as this WRX(sound insulation?).

 

 

Has anyone else hit this kind of issue and how much labor (time involved)? My wife with poor hearing thinks it sounds like an airplane taking off.

[Max Capacity]

Video didn't work for me, but I'm guessing the turbo is close to going out.

 

You may want to think about pulling the down pipe and check for shaft play.

[__raj]

I thought turbo too however wife shut off motor going 65mph and noise still there. It's a whirring noise.

[JmP6889928]

I noticed actually two distinct sounds in this video. My assumption is that your concern is with the second sound.

 

At the beginning of the video when he was revving it up with the car stationary, it sounds like it certainly could be the starter drive has not disengaged and is spinning on the starter shaft via the flywheel. The high pitch whining is definitely something to do with a small bearing and could also have been alternator or PS pump bearing going bad too. Doubtful that it's turbo as it made the noise at fast idle before the boost would have come in and continued even when he revved it, going up and down the scale with RPM change.

 

The noise when he's driving the car that doesn't change with RPM tells you that it's definitely something in the rolling drive train and NOT clutch related as that would move up and down the scale with RPM and it doesn't. In this case, it COULD be a transmission bearing or even possibly a U-joint in the driveshaft. In RWD cars, that kind of noise can be generated by bad U-joints or a bad center carrier bearing. It could also be an axle with a plunge joint (inside CV joint) going bad as I've seen them begin to develop excess clearance inside and make all kinds of harmonic noises. A couple of other things I would check first though.

 

You said that the noise continues while coasting out of gear. Does the noise diminish when you push on the brakes? Does it remain consistent in pitch and volume through that entire range of MPH you posted?

 

The other thing that you could check and it would sound goofy but it can be related to two different things working together to cause the noise. First, check and make sure that ALL of your heat shields are tight and don't have ANY cracks anywhere-not around the bolt holes, not in the edges anywhere, not on the clamping straps, none. If you DO find a crack, use something to cut it out of there. If it's on the edge somewhere, cut a small chunk out further back than the crack end. If there are cracks around a bolt hole, grab some rubber washers and fender washers at the hardware store and remove the bolts and place the rubber washers on the inside and the fender washers on the outside between the two mounts to separate the mounts from each other, isolating the heat shields. Don't neglect the front exhaust manifold heat shields as these, too, can cause the noise. The bank 1 side (PS) can easily vibrate if there are any broken mounts (ask me how I know) and can cause any number of noises. If you do find something, this alone may take care of the noise. Any cracks can cause the aluminum to vibrate down the length of the crack as the two sides work out of sync, and the flat part of the heat shield can act as an amplifier to increase the volume.

 

This brings me to the second part of the equation. Have your wheels balanced (finger balance is best) after you've done the above. Harmonic noises are usually caused by the smallest of vibrations, not large vibrations. The high speed tends to make me think that it's the combination of the two-wheel balance (or cupped tread due to misalignment) and a cracked aluminum shield somewhere. Have the tires examined very closely and make sure that there is nothing stuck in the tread or they're not separating. Look for the cupping or uneven wear and if it's there, either replace the bad tires or move them around and have the car aligned.

 

Good luck.

[__raj]

The sounds are in time only with the speed of vehicle(40-70MPH) nothing else. Above 70mph wind seems to drown it down.

 

Car made the exact noise irrelevant of the motor on/off, revving high or low, or clutch in or out.

 

Sorry about the vid, it was supposed to advance to 1:40 according to youtube link I pasted.

[Max Capacity]

Can you ride in the back seat while she drives the car. You'll be amazed at what you can hear from back there.

 

 

 

Is there any steering wheel shimmy like tires out of balance ? I'm guessing may be a wheel bearing.

 

Still haven't heard the video.

[__raj]

It turned out to be a wheel bearing and $240 to replace. Odd it just one day started making a lot of noise and was not gradual.