My 2004 XC70 started with an engine noise just two days ago, it is not noticeable if I stop, but as soon as I am moving, or give it a little gas, the noise is there, like a humme type of noise, loud enough to be noticeable.

It has 95k miles, I just did all the regular jobs.

Only thing I can recall, is that my daughter pushed the shift to stop, while it is still 1~2 mile/hour (she is trying to get her driver lic. ;-) ). but I dont think it is related.

any thought on what it might be?

TIA

 

Maybe engine mount bad?
Does it start at a certain speed everytime?

 

thanks tech.

I just checked it, it is kind of winddy noise, like whool-whool type.

it is not related to engine rev.

when I was down hill/slope, engine was idle, but the noise is still there, seems it is related the movement of the car.

may be the hub, bolt joint in trouble?

 

I am thinking maybe front wheel bearing might be bad. Usually when they go bad the noise starts at 30 MPH.

 

is there reliable way to confirm that front bearing?

I guess I can do some searching off the forum...

 

Not 100% unless you pull the bearing and check it. But a bad feathered tire can give the exact same noise.

 

I had new set of General Altimax HP two months ago, there were some folks complaining "noise" (some dont) off Tire Rack review, could it be the case that after certain time the tire noise started? or it is with tire day one?

The noise is definitely recent, since my wife complains it just today, as I noticed it today, she said it was started couple of days ago.

is there a way to confirm the tire noise , vs wheel bearing one?

I was thinking to bring it to dealer, but hesitated, since I know dealer will charge a factor of 10 on price (a simple hitch installation would be 400, vs, 40 from local CapWorld, for example) ;-(

I dont mind to pay more for good services ;-)

thx

 

Try rotating the tires and see if the noise goes away. If it does then you know it is the tire. If it does not then it might be the bearing.

 

super, will try that...

thx tech, appreciated the advice.

 

Your welcome

 

just a follow up on the thread.

I finally changed the LH HUB, and now the noise is gone. Here are some of the details:
- I shopped around on independent shops, most charge about 150 to 200 for the job, 200 on the parts, not too bad
- interesting enough, Merchants Tire, quote a lab of of 200, but parts 400
- dealer did not response to the request of the quote

- I brought the parts from FCP, the part itself actually comes with the bolts for the HUB, and for drive shaft, but the web site note tells you to order the bolts, so I end up with additional set of bolts, not big deals, around 10 bucks.

- I was concerned about taking the drive shaft out of the HUB, when I read different posts, it ends up pretty easy, a gentle tap did it.

- Haynes manual has good tips on how to loose the drive shaft bolt: do it before you take off the wheel when the car is on the ground, much easier (if you dont have air tool)

- more trick part for me is to lower the control arm after loose the ball joint nut. the VADIS method worked, it is just that I did not have a good leverage on my tie-down, a bigger one might helped. so I end up combine it with Haynes manual method, use a long iron pipe to press down the control arm.

- somehow I could not find the torque spec for the bolt of drive shaft in VADIS, Haynes manual says 35 nm + 90 degree (HUB bolts are 25 stage 1, 65 stage 2, then 60 degree)

- an air tool is nice, I will try to get a bigger tank (like20 gallon one), without it, a good 1 ft or two long iron pipe can be a very effective leverage extension.

last, thanks to Tech. Tech was right on my first description of the symptom

 

Glad all is good now!