I have a 2000 VW Passat Wagon with 115k miles. Great car. The 1.8 Turbo runs fine. However, while driving I hear a harmonic coming from the front right. It is very noticeable. The brakes and bearing have already been replaced-needed it anyway- but the sound remains. I am now thinking that maybe the tire ply have separated. Any ideas?
There are a number of things that might cause a vibration.
You didn’t mention the speed you sense this at, but typically, stuff that is tied to wheel rotation is sensed in the 50 to 70 mph range. If you are getting the vibtaion at a different speed, it is probably not tires, rims, imbalance, out of round tire and rim, etc. - and that would include a separating tire.
With 115K. I would tend to think CV joints.
But because this is so very important, I am going to describe how to tell if you have a tire separating:
First, the vibration will normally occur in the 50 to 70 mph range, just like an out of balance tire would. You might feel the vehicle “lurch” as you go around a corner, and the “lurching” with be rythmic:
“lurch”, pause, pause, pause, “lurch”, pause pause, pause, “lurch”, pause…etc.
This "lurching will be more detectible if it is the front tire separating.
Please be aware that the “lurching” does not necessarily mean the tire is separating. There are several other reasons why this might happen.
Also, a vibration by itself does not mean a separating tire. The vibration would have to be getting gradually worse, generally over the course of several hundred miles.
Again, a vibration getting worse is not proof of a tire separating. There are other things that can cause this, including irregular tire wear caused by misalignment.
If you get to this point - or at any point in this detection process - stop and look at the tires. Rub your hands around the circumference (the tread) of the tire (It helps if you wear gloves!) If there is a bulge in the tread, or a worn area about 6" long in the tread shoulder (and only there!), then IMMEDIATELY remove the tire. If you can’t do it yourself, then drive SLOWLY to the nearest tire shop (under 30 mph will be OK)
But if you have inspected the tire and didn’t find anything, don’t think that a reinspection is of no value. These separations grow and you may detect the vibration long before the bulge is visible.
Hope this helps.