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Once I drive for 50 miles or more, I begin to hear a loud whining sound. I took it to the shop, they said my wheel bearings were worn out. They replaced the bearings on the wheel. I got my car, took another trip, still heard the loud whine after ~50 miles of driving. I took my car back to the shop, they replaced the set of wheel bearings on the other wheel. Now I've been driving 50 miles, and I hear this sound again.

If you've ever wound a hand-crank charged flashlight, its exactly like that sound. Identical. The faster you wind, the louder the whine sound gets. And then it continues for a moment because the spinning part inside is spinning for a second or two after you stop cranking it.

Well that's exactly what happens when I push the gas pedal on my car, but only after driving a long distance.

Are these details enough for someone to know what component of my car is having a problem?

migrated from engineering.stackexchange.com Sep 9 '16 at 23:54

This question came from our site for professionals and students of engineering.

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    @DaveTweed Thanks for the advice, ill follow it on both counts. And sorry, I shouldve included my model, a Nissan Altima 07. No modifications from the standard engine. – Viziionary Sep 9 '16 at 21:25
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    AFAICT, no stock Altima has a turbo, so that's out. The first thing to do is determine whether the sound is coming from the engine itself or the drivetrain. Once it starts happening, does it continue to happen if you come to a stop and rev the engine in neutral? Or is the pitch always related directly to the speed of the car? – Dave Tweed Sep 9 '16 at 23:57
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    @JasonC Tested! Absolutely no sound while stopped, revving in neutral other than typical engine sound. Also tested turning off radio while making the sound, removing aux cord too - they seem to have zero effect. The sound continues once I keep driving. – Viziionary Sep 11 '16 at 22:14
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    @JasonC Automatic. It's most closely tied to how far I have the gas pedal pushed. I say that because the sound seems about the same when the engine is doing less work. For example, I hear it on the interstate at 80mph. I exit and stop to perform the neutral tests as requested, and then I continue on a road at a lower speed, hear it as I accelerate to 50mph, then rev to 55 to see how it sounds. Reving from 50 to 55 it sounds about the same as reving from 80 to 85. And the sound slowly dies away after 5 minutes of being off the interstate / driving slower. – Viziionary Sep 11 '16 at 22:47
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    @JasonC so work being done is a factor, since it only happens while the engine has been doing alot of work for about 2 hours straight. And to clarify further, the sound is an immediate effect from pressing the gas. For example if I press the pedal hard for 1 second, the sound peaks at the furthest the pedal is pushed, then dies away during the next 2 seconds. – Viziionary Sep 11 '16 at 22:50
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The 07 Altimas (the automatics) have a CVT that seems infamously noisy from cursory research.

Is it like the noise you hear around 30 seconds into https://youtu.be/WblGvAPPGX4?t=30? It's tough to hear over him talking but you can hear it "winding down" in the background when he pulls his foot off the pedal.

Apparently there are a lot of complaints of transmission noise and issues in the circa '07 Altimas.

In fact, Nissan seems to have released a service bulletin on 4th gen Altima about transmission noise, which seems to state that it's more of an annoyance than a problem. From http://x.nissanhelp.com/forums/Knowledgebase.html?linkid=3069&catid=400:

2007-2009 NISSAN ALTIMA SEDAN, 2008-2009 ALTIMA COUPE; WHINE NOISE FROM CVT AT HIGHWAY SPEEDS

A whine or grind type noise heard during acceleration and / or constant highway speeds.

The level of noise may increase as vehicle speed increases.
AND
There are no other drivability issues or stored DTCs related to the CVT.

Also you might even still be under warranty. Apparently Nissan extended the powertrain warranty to 10 years / 120,000 miles, so if you haven't hit 120k yet and it looks like a transmission issue talk to the dealer about a warranty replacement, even if the sound isn't causing a drivability problem because, hey, free transmission.

So, maybe this is the cause. It sure sounds like your description. I would take it to a dealer to get it checked out, and possibly draw attention to the service bulletin, rather than a third-party shop.

  • Sounds exactly right. – Viziionary Sep 11 '16 at 22:52
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Fist thing is to check that the bearings have been torqued properly, over tightening is easy to do and a common problem on newly replaced bearings.

Also if one bearing goes it is sensible to replace the other side at the same time. It is also very easy to get grit in the bearing grease whcih can cause very early failure.

Equally it could something entirely separate. engines have a lot of ancillary party with high rotary speeds especially belt driven pumps for oils, coolant and air conditioning.

Typically a failed wheel bearing will be noticeable louder on cornering, especially on the loaded side (ie right side bearing on a left hand corner).

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