Strange noise at 45mph
 

Hi there. Just recently I've started getting a noise just like grinding metal - like a blade being held against a sharpening wheel - at exactly 45 mph. It stops when I go beyond or beneath 45mph. Very strange.

Any ideas?

do you have any idea a general location of where the sound is coing from? Could be many possiblites.

It's hard to pinpoint exactly because it only happens when I'm moving at 45mph - so I can't open it up to see, but it does seem to be coming from the engine well down in the right hand section (as you look at the engine with the hood up). That's how it sounds when the windows are closed, which would put the problem on the opposite side to the air filter and timing belts. As I say though - it's really hard to pinpoint while I'm driving.

One other thing - it happens regardless of whether I'm coasting or driving and whether I'm speeding up or slowing down. Always exactly at 45mph.

Thankyou for having a think about this. I appreciate it.

ok sounds like it coud be a doozy:( what year passat and model do you have?

It's a 1994 cl saloon. I took my wife out with me yesterday to try to pin down the location of the noise and it seems to be coming from the middle of the engine well. It sounded like the right from my side, from the left from her side, so when she got up close to it she said it was coming from the middle.

It also makes the same sound, only much quieter, at about 63mph. It's really loud at 45mph though.

Does that sound like a drive shaft issue to you? Any suggestions you may have would be greatly appreciated because I'm nonplussed at present.

Its possible that could be the issue. Or, there could be something wrong with another suspension component that is making it vibrate through the driveshaft and back under the hood. I had somewhat of a similar noise on a relitives car but it was a ford taurus and I replaced the wheel bearning and it was gone. I would pu the car up on jackstands and see if you can grab the tire from top to bottom and try to wiggle it. If there is play then that could be the issue. If you do this from side to side then it could be a tie rod end that is worn out. If you remove the tire, you can grab the drive shaft and, it will have some play in it but, if you notice excessive play it should be replaced. Hope this helps.

I'll definitely check that out. Thankyou for the input! :)

When the car is makeing this noise and you move the steering wheel left or right will the noise change ?? if so the right wheel bearing is bad ..more than likely..

It doesn't seem to change when turning, although there is another loud vibrating noise that's started recently that gets louder the faster I go - that one lessens a bit if I'm turning hard left.

The new noise sounds like I've got the car in too low a gear, but it seems to be coming from the rear of the vehicle and happens whether I'm in gear or not.

Yep - the rear right hand wheel has a little give top to bottom. Also, the suspension creaked alarmingly and made a slightly squelchy noise both when I lifted it up and put it back down. I think I need to take the car to a VW mechanic.