Low humming/rumble after 38 mph. CVT problem???

[Karasu]

That is certainly good to know. As I stated in my first post, they just reprogrammed the CVT and I noticed a slight reduction in the noise along with more realistic readings from the instant fuel consumption. Your information and Ronzuki´s suggestion about using the manual shift to up the revs might work. to reduce the noise. I will try that today.

[KuroNekko]

I don't think it's the wheel bearings. My former car, a Mazda3, had two sets of wheel bearings go out so I got used to the symptoms. When worn enough, the noise will occur at all speeds. You can especially tell when you are cruising and tilt the wheel from one side to another lightly, to kind of toss the weight of the car from side to side while going straight. With worn bearings, you can hear the bearing noise get amplified when more weight is on that side for a second.

Worn wheel bearings also make noise and vibrations when the wheel/tire is rotated by hand when the car is jacked up. If you can shake the wheel/tire while everything is bolted on, then the bearings are worn out.

I had such bad luck with OEM wheel bearings on the Mazda3, that after my second set that only lasted 26,000 miles, I got aftermarket wheel bearings. Much like the other problematic parts of the car, the wheel bearings had FoMoCo stamped on them.

I can't comment on the Kizashi CVT transmission as I have a 6 speed manual.

[Karasu]

Hello KuroNekko.
I agree that it is unlikely that the bearings are damaged. I already performed all the tests you mentioned in your post and none of them can prove something is wrong with the bearings:
1.-Noise only happens after a certain speed.
2.-I tried tilting the car to see if I noticed any difference/increase while shifting the weight from side to side and there was not any change.
3.-With the car jacked up, the mechanics could not perceive a single noise coming from the wheels while I, inside the car still heard the noise.

I also followed the suggestions of NJKizashi2 and Ronzuki about manually shifting speeds when I noticed the noise to check if it would change/diminish at higher rpm´s.

Now I´m really confused because when i did it, the noise was steady and related to the speed of the wheels and unrelated to the shifts I was making. Although I could hear the motor reving up, the noise kept steady and could not notice any variation when I could clearly hear the motor reving up and down when used the paddle shifters.
Actually, If you just leave it in neutral and go downhill, the noise will be there regardless of the revs.

[ipaqxman]

OK, if you're feeling it at all, and in the steering wheel (even though the car's have electric steering)

Ron are you saying with electric steering you are not feeling any vibration through the steering wheel? I feel every road uneveness and little bumps well through the steering wheel. Is that abnormal?

[Ronzuki]

To my knowledge, the steering is 'drive by wire'. No real mechanical connection to the steering rack via the steering wheel. Servo/stepper motor 'gearbox' so to speak. That said I've never poked my head up under the dash to see what makes it all tick. I do recall seeing a pretty extenxive YouTube vid before I bought mine going over the entire suspension system and if I remember right, they had pointed out the electric steering. I feel every little bump in the road as well, but from the entire car's reaction to it not specifically through the steering wheel. The suspension is tight and the tires are very low profile. It's very different than when I hit something in a vehicle with a conventional steering setup whereby the wheels end up, via mechanical means, tied directly to the steering wheel. You get a very mild case of what we call bump-steer in the off roading world.

To the OP, thankfully, it sounds as though your tires are slightly out of balance and you don't have a CVT issue.

[Karasu]

To the OP, thankfully, it sounds as though your tires are slightly out of balance and you don't have a CVT issue.

Ronzuki:

Do you think the wheels being out of balance will cause the noise even when not touching the ground?
I had the car lifted twice and the noise was there even with the car in the air.

[Woodie]

To my knowledge, the steering is 'drive by wire'. No real mechanical connection to the steering rack via the steering wheel. Servo/stepper motor 'gearbox' so to speak.

No, that would mean if the power went out you'd have no steering at all, no one would build a car like that (nor would they be allowed to). It's electric servo motors assisting the mechanical steering gear, just like standard power steering is hydraulically assisting the mechanical steering.

[Ronzuki]

To my knowledge, the steering is 'drive by wire'. No real mechanical connection to the steering rack via the steering wheel. Servo/stepper motor 'gearbox' so to speak.

No, that would mean if the power went out you'd have no steering at all, no one would build a car like that (nor would they be allowed to). It's electric servo motors assisting the mechanical steering gear, just like standard power steering is hydraulically assisting the mechanical steering.

Excellent point, thanks for clearing that up. I need to poke around under there and see what's what. Damn cars are so cramped underneath and low to the ground though.

[Ronzuki]

To the OP, thankfully, it sounds as though your tires are slightly out of balance and you don't have a CVT issue.

Ronzuki:

Do you think the wheels being out of balance will cause the noise even when not touching the ground?
I had the car lifted twice and the noise was there even with the car in the air.

Theoretically I suppose it could, in fact I'd imagine it would be worse with your CV shaft angles being so severe while running it with the wheels off the ground. I get a little rumble (like unbalanced tire) after my car sits for a few days over a weekend...flat spots in the tires I imagine. After 10-15 miles it smooths out and all is good for the week's jaunts to work. Speaking of CV joints, did the mechanics thoroughly check them for a possible defective unit? A worn or ungreased CV joint would give a rumble that you'd feel and hear. Hard to believe one's bad with such low mileage, but anything's possible.

[Karasu]

Ronzuki:

Since I´m trying to rule out every possibility, I guess it does not hurt to have the wheels balanced and see if it makes any difference. It is a lot cheaper than trying to change a bearing and see if there is any change.