2001 Nissan Pathfinder noises

Is this vehicle 2wd or 4wd? Also, if the wheel bearing was locked up, the wheel would have stopped turning. Did that happen? The whistle you hear, does it continue after the engine is off? As far as the price for a sensor, can you explain further?

First of all, if you're hard-of-hearing, how is it you're hearing noises four mechanics aren't? I actually did run into this many years ago, and that person had a very selective range of frequencies he could hear. He was hearing wind noise from turbulence around the driver's door frame. The clue was he couldn't hear it when riding in the passenger seat. You might consider temporarily running some tape around places like the windows and wiper arms to eliminate those as possible suspects. For people with normal hearing, all the other car sounds drown out most wind noise.

It should never be necessary to replace all four oxygen sensors at the same time unless they were damaged by a running problem that dumped too much raw fuel into the exhaust system for a long time. What was the symptom leading up to that? The sensors can have different prices. The front and rear ones are measuring different things so they can be built differently. One may need to be made with longer wires, or one could use a less-expensive standard plug while the one on the other side of the car has a special plug so the two can't be mixed up.

Not sure what the concern with the parking brake is. It's common for the cables to stretch with use, and they do have to be adjusted from time to time. The mechanic may have tightened it a lot last time so it wouldn't need to be adjusted again for as long as possible. I never counted the number of clicks, but as long as it fully releases, the adjustment is fine. A standard part of the tightening procedure is to verify neither brake is dragging when the handle is fully-released. If they're not dragging, there's no need to relax the adjustment. There's a lot of flex in the cables too, so even when the brake is fully-applied, you can still pull the handle some more. I think you're unfairly blaming the mechanic for doing nothing wrong. If you feel otherwise, the last thing you want to do is not go back. He deserves the chance to correct his mistake if there was one, or to explain why he may have done something a certain way. When you run to a new shop every time you're dissatisfied, you have to pay again for any service, and you're going to be throwing so many new variables in that no one is going to know who is responsible for what or what was done in the past. There are a real lot of things mechanics do for a reason that we can incorrectly interpret as incompetence, fraud, or just plain laziness. I'll never defend a dishonest shop or mechanic, but so far you haven't given any reason to be concerned.

Not sure what to make of the wheel bearing issue. If it was seized, you should have had other symptoms like wobbling, or a grinding noise.