'05 Odyssey, 160k miles

I'm in the process of t'shooting the source/cause of a metallic scaping grinding noise from the front end.

Here's where I'm at:
- oscillating noise whose rhythm changes with speed btwn five and thirty-five mph;
- intermittent, with no obvious cause for sudden onset;
- comes from the front of the van; can not determine which side from inside van or when driving past a wall or with someone listening as I drive past;
- does not occur when up on jack stands; only occurs under moving weight of vehicle;
- the brake dust shields and pads are not the source/cause;
- occurs when transmission is in neutral or engaged;
- no dangly metal bits under front of van or resting against moving parts.

With brake dust shields/brakes eliminated I next suspect a CV or wheel bearing. But the sound symptoms for these parts don't match. A failing CV clicks, while a failing wheel bearing makes a grinding noise regardless if the wheel is spun under load or up in the air.

I'm stumped.

Thoughts? Suggestions?

 

I picked up a small stone in the brake pad area after they chipped and tarred a nearby road, that gave similar symptoms. Consider obtaining some "chassis ears" to help locate the sound. Swap sides for the two front wheels. Look for any scrape marks adjacent to anything that is moving while the sound is occurring.

 

Kind of, I immediately thought wheel bearing when you said "only occurs under moving weight of vehicle." Bearings making noise on jack stands is only if they are really bad, sometimes the wheel bearing doesn't make noise when on jack stands. I couldn't get several wheel bearings to make any noise at all on jack stands, but I could definitely hear it when driving down the road. One Honda Fit I had to push (harder than I was comfortable with) in on the front drivers wheel towards the engine bay. When I turned the wheel back and forth, I could feel the grinding from the bad bearing, but I still couldn't' hear any noise. BTW: did you remove the brake pads, and brake caliper when you had the van up on jack stands, and turning the wheels checking for the bad wheel bearing? On a 2006 Pilot 2wd, I couldn't tell which rear wheel bearing was out, so I jacked it up, and put a socket on a drill, and spun the hub up to highway speed using the spindle nut. At drill speed, that bad bearing sung loudly that it was bad. Then I did the other side, and it also said that it was bad, just not as bad as the passenger side. I still need to change drivers side out, but once I fixed the passenger side and did the same drill test. It made no grinding sound when spinning it up with a drill.

As coder47 mentioned above, I also had a very small piece of flint rock stuck in the brakes that made a horrible sound, that I didn't drive it, until I could locate the problem. It sounded worse that when brake pad wear indicators screech out.

 

Following symptoms means wheel bearing is bad:
1. noise increase with speed
2. louder at certain speed
3. noisy even in neutral gear

Intermittent - bearing is at the beginning of failure

You can put the front on jack, and move the tire at 3-9 o'clock, and 12-6 o'-clock to observe any minor movement. There should be 0 movement, else wheel bearing is broken