[Solved] Growling Bearing Noise (2.7L) 2TR-FE

Maybe. When they start to whine it can be a sign that its starting to struggle. With the dmm hooked up, start turning electrical loads on (wipers, blower motor,etc) and make sure it's still in the 13.5 volts and up range.

Also, dumping oil on it is backyard AF!
If the alternator is working good and he dumps oil in there it will become a soggy mess that will attract dirt. There are cooling vanes in the alternator case that need to be clean to allow heat to transfer

 

Yeah maybe so, but it won't damage the alternator, isn't nearly as bad as salt sludge, and he's planning on throwing it out anyway.

 

If it overheats from oil contamination its getting damaged and will eventually fail. I've had to tell customers that I can't warranty an alternator when there is an oil leak directly above it (like a valve cover gasket)

 

It won't. You greatly overestimate the thermal insulating effectiveness of an extremely thin coat of oil. FYI: oil is actually a pretty good conductor.
And for that matter, since those cooling fins are going to have fairly significant oxidization on their surfaces (which *is* a GREAT thermal insulator), a bit of oil actually can IMPROVE the cooling.

 

so the next time I have to send a defective alternator back to the parts store and they deny the warranty due to it being covered in oil, I can give them your phone number and you'll get it all straightened out for me?

 

LMAO

 

I just pulled the dipstick on my alternator.... was a little low.

 

Well unplugging my alternator didn't do a thing for the noise...do i rule out the alt?

 

Make sure it charges properly when a bunch of electrical loads are turned on. Get a stethoscope and start listening around on all the pulleys as mentioned above.. or take the belt off and start spinning pulleys around. Any rough scratchy bearings should be replaced

 

Placed stethoscope at the location shown in the above post. Sounded much louder than similar areas around other pulleys. However earlier when i disconnected the green connector on the alt noise was still there....maybe just the pulley is bad?

 

The bearings that support the shaft inside the alt. are what's gone bad. You can take the alt. apart get the bearing #s hopefully and look them up online and order new ones. Or just go with the Denso option.

 

I checked my coil and it was low so I added some more.












































Probably only the real gear heads or old fuckers will get this one.

 

Then why did the sound not go away when I unplugged the connector? BTW I am not trying to be annoying, honestly just trying to learn.

 

The whine I was talking about is a magnetism whine when the alt is struggling electrically. You can still have a whine from simply bad bearings too. You're on the right track.

Take the belt off and spin the alt pulley, it may be loud just spinning it by hand

 

The bearings making noise and the magnetic field causing the noise are 2 different things. You have to have bearings to support the shaft that goes through the alt.
Here is a somewhat decent pic for you to understand the innerds of an alt.

 

Here's a better one

 

Guys thank you very much for the explanation, I now understand a lot more about alternators. That diagram helped out.

Hopefully I can go one more week with the stock alt for right now...after next Friday I am offwork for nearly two weeks and would like to work on the truck then.

 

For some reason it wouldn't let me quote you also. Thank you as well lol

 

Dude all that'll happen is it makes noise until the bearings finally give up and come apart. I drove around with my idler pulleys and tensioner pulleys howling like crazy for months.