Whine from the Engine

[BlackYJ]

I have been having this whine coming from the engine for a little while now, but lately it seems to be getting worse and I am hoping someone can help me diagnosis it as it sounds like a bearing is starting to go.  Here is some info

-The whine is loaded when the engine is cold and seems to quiet down once the engine is warm
-The whine gets noticeable when teh rpms get above about 1500 rpm
-The whine does not increase when i turn the steering wheel
-My voltmeter is showing the current amount of volts while running
-If my rpms are above about 2000 and i let of the gas, i can really hear the whine
-I can't really hear the whine when i am above about 70 km/h, but that is probably because there is too much wind noise

I have not had a chance to check it out, but I am thinking that it might be my fan clutch.  Any other suggestions?

[FiEND]

borrow Bill's 4 foot screwdriver and listen to it whilst touching engine parts.  not perfect but sure can work

[rws]

Alternator or belt tensioner could be likely culprits.  Buy a cheap stethoscope from the local parts store and see what you can find.  If it is the tensioner the dealer version works far better than the generic versions from Napa or Parts Source.

[BlackYJ]

Alternator or belt tensioner could be likely culprits.  Buy a cheap stethoscope from the local parts store and see what you can find.  If it is the tensioner the dealer version works far better than the generic versions from Napa or Parts Source.

I thought that if the alternator was starting to go, the voltmeter would run high.

Also, i don't have an automatic tensioner on my YJ.  The belt tension is set by the PS pump.

[Rookie]

I thought that if the alternator was starting to go, the voltmeter would run high.

Only if the voltage regulator is toast

Buy a stethoscope form PA and listen to the alternator front and back (it has 2 sets of bearings) power steering pump ,water pump, a/c compressor (if you have one) and any idler pulleys what your describing sounds like a bearing somewhere

HTH

Steve 

[BlackYJ]

I was definitely thinking bearing and teh alternator is the stock factory one so after 5 years of wheelin it might be ready for a new one.

[BlackYJ]

Well funny story about this whine.  Since it was warmer yesterday afternoon, i had just a faint whine, but after leaving the gym last night once the temp dropped, I had the whine again.

I took a quick look last night and the fan clutch seems okay.  I did the long screwdrive test, because i don't have a stethoscope, the alternator seemed fine, but the PS pump sounded like there was some grindage.  I did not test the water pump.  I will probably try to have a better look at it in the next little while.

[Gearhead]

I thought that if the alternator was starting to go, the voltmeter would run high.

Also, i don't have an automatic tensioner on my YJ.  The belt tension is set by the PS pump.

Check the idler pully . 
The bearings in the alternator can be totally thrashed and have no effect on the electrical output  , I'm not saying yours is toast though.
The power steering pump , because it is a vane pump , is going to make noise when listening to it through a screwdriver or stethiscope , don't be fooled by this.

How tight do you run your belt ? ,  these need to be set with a guage to be truly accurate , or to get max belt life and not put stress on accessories.