My 2001 Nissan has noisy blower. Sounds like a airplane when it's on 2-3-4. Replace blower?

Make sure the oil filter is fitted with a return valve, some after market filters don't have this valve, and the oil drains back to the sump when stopped, It takes a second or two after starting to build up pressure with type of filter, so there is a rattle.

Most likely the blower motor resistor has burned out. It is pretty easy to replace - search online for instructions.

You need to have the wheel bearing replaced ASAP.

if your blower motro only works on the #4 setting you need a resistor.cheap and easy to change.located next to blower motor under pass. side of dash.two phillips screws secure it.if it fails again replace blower motor as it is drawing too much current and overheating resistors.let me know how it turns out.

Bearings in the blower motor are shot. Only fix is a new blower motor. If you have no experience in auto repair, I would take this to a qualified shop, as most of the time you will need to disassemble the dash to get to it.

the noise is a wheel bearing , turning left to right should isolate wich side , the niose will increase on the noisy bearing side

this is caused by a bad fan resistor, the resistor has differant size coils for each speed. if a coil fails then you will lose that speed.

Blower motor sounds like it is going bad and the bearings are giving you the noise. Motor going bad is the intermittent problems...bearings getting hot and motor is "reacting" to this.

Remove the belt and check all pulleys for smooth operation. any binding at all is amplified when belt tension is applied. also check the belt itself...If it's glazed or dried out, it can be noisy.

I enjoyed the same problem on my 2001 Nissan Sentra three months after I moved to Florida from New England. It is not a fuse; the fan would not work at all if it was a fuse. Your problem is the fan motor resistor behind the glove box. The classic symptoms are that the fan will not operate except on 4 (full speed). You technically could replace it on your own but I took it to my Nissan dealer and had it replaced for under $100, parts, labour, tax, and coffee.