Varying degree of vibration over 60MPH
 

I recently bought a '98 V70 XC. Automatic with 175K (yeah I know). Took two road trips recently and had vibration felt both in the steering wheel and in the seat/floorboard. What gets me is the vibration varies from nearly nothing to a light vibration to a full shimmy(only happened twice). This only happens over 60mph, but more prominent @ 70mph. The vibration is speed related and doesn't change under acceleration, deceleration, braking, or car in neutral. It seems independant of road condition (driven from freshly paved to well worn).

Steering feels fine and no back pressure. It doesn't wander or pull either.

I'd normally think it would be unbalanced tires, but I've never had that sensation vary. It doesn't vary up and down sparatically, it's that I've felt the vibration for stretches and different stretches have felt different.

I can't be 100% sure, but I believe the vibration isn't there/very minor for the first 5 miles of highway travel, but is certainly noticable at the end of the stretch. Could just be my perception though.

I'm getting new tires anyways, but I'm not sure that's it. Struts are worn so I know that's coming up, but I've had cars with worn suspension before and not felt like this.

Any input would be appreciated.

My first suspects would be the tires to

Thanks for the input blackbrick and you're right. Ended up getting new tires last night and that was it. I've never experienced bad tire/out of balance that wasn't consistant. Guess I made this thread prematurely, but the varyiance is what threw me off. Still need new struts and probably worn ball joints too, but new tires fixed that vibration.

2 more problems: vibration & whine
 

Hello again, new tires and new front struts fixed most of the drivability, but the intermittent vibration is still there.

After the car has been driving for a while on the HWY (10+ miles or so), there's a vibration. I haven't noticed it on 90% of my driving, but definately on longer drives it seems to come up. It's not a shimmy or anything sever, but just a vibration/humm felt in the steering wheel and in the seat/floor. It seems worse at HWY speeds (50+), but can be felt as low as 35. Throttle possition doesn't seem to be a factor nor does braking. Shifting to neutral doens't seem to affect it either. The steering and suspension feels fine as does vehicle performance. No noise seems to accompany it. Any ideas?

I also have a whine at speeds noticed over 30mph. Although I can experience the noise at lower speeds it seems more noticable on the HWY. This seems to be throttle position sensitive. When letting off the gas or accelerating, the noise isn't present. It's only when the throttle is slightly pushed, basically maintaning speed. It isn't a loud noise, but becomes annoying on a longer drive. seems to be coming from front of car/under hood. Shop where i had struts replaced told me the angle gear was leaking (they repaired leak) and that was most likely the noise. They said that damage was probably already done and only way to get rid of noise is new angle gear. After researching the angle gear, that doesn't seem to be the same syptomps. Any thoughts?

Thanks in advance for some input.

Have you check your inner CV joints on your axels? They will cause vibrations during acceleration and also at highway speeds. I just pulled my axels out and took them to someone to rebuild while I was rebuilding my front end. Thankfully they did not need anything but new boots and grease. There seems to be a lot of issues with these joints on these cars.

thanks for the response. The vibration doesn't seem to be correlated to rpms, throttle position, or acceleration/deceleration/trans in neutral. could the cv joints still be the culprit? my experience with bad cv joints was noises while turning while accelerating. is there a way to check these?

Grab and hold the axel behind the inner CV joint and try to hold it still while you try to move the outside back and forth. If you hear any clicking/popping (any noise) or if there is any play or slack in it you may have a bad inner joint. Also, make sure that your boots are dry and not leaking and do not have holes in them. If so replace them asap.