so...98 forester, almost 200k miles.

 

i'm used to a farily loud car as mine has an aftermarket header and exhaust. at interstate or highway speeds recently, i can hear some noise from the back wheels. it's fairly loud. my mind wants to make it into the sound you get from grooved pavement, but it's not that because i can hear normal tire on pavement sounds coming from the front wheels.

 

i figure it's one of three things, but i'm not a mechanic, hence i'd appreciate some input from the forum: wheel bearings? out of alignment? rear dif?

 

thanks for any input.

Those would be all possiblities. Wheel bearings would be a good suspect at that mileage, plus Foresters and Imprezas did have some issues with those in the rear around that time. Sometimes if you shake the wheel hard with your hands you can feel the looseness, but not always (can be noisy way before you feel any looseness).

thanks for replying. i drove from lincoln, ne to kansas city and back, over the summer and there was no odd noise that i remember, so this is a relatively new thing. off to the mechanic soon...

Sounds good. That would be line with how things usually fail. For a while it works, then later it doesn't.

I would highly suspect the rear wheel bearings. I've done more on earlier Foresters and first generation USDM WRXs then any other years with pressed in wheel bearings.

Wheel bearings - they used ball bearings on the Forester and Impreza and the fix is to install the Legacy roller bearings. If you let them go too long you will also likely have to replace the hub.

 

GD

Wheel bearings. Have someone sit in the rear to determine which side it is.

Loading one side in a moderate-speed turn can also help to isolate which side it is. If a slight turn to the right produces more noise, its the left rear. Another way is to jack up the rear, disengage parking brake, and turn each rear wheel while holding a breaker bar against the strut/coil and up against your ear like a stethoscope. You'll hear the vibration loud and clear if its the wb.

If you have all wheels off the ground, rotate each wheel with one hand and place your other hand on the spring coil. Any roughness in the bearing will transmit to the spring and be felt through your hand.

If you have all wheels off the ground, rotate each wheel with one hand and place your other hand on the spring coil. Any roughness in the bearing will transmit to the spring and be felt through your hand.

 

This can also point you to the wrong wheel, or not actually happen even if the wheel bearing is making a lot of noise... Look a few posts down for my 2000 outback

thanks forum folks for all the feedback. i haven't had the wheels off the ground yet. one thing i am noticing, is that the noise isn't just at highway speed, as i first stated. it's pretty much always there, just increases quite a bit at 45+mph. you can hear it at 25 and 30 tho too. noise builds with speed and drowns out my usual purr. luckily we are still in biking weather...

just following up here. new wheel bearing fixed it. it was just one side, the driver's. it sounded like both to me when i was driving. all is good. almost 200k.