Alternator
 

1989 300E 110k

Alternator was making a howling noise after I got off the freeway for about 10 minutes then went away. No other issues were noted.

Any thoughts?

Hot bearing??

They are replaceable

It might be your alternator...

Bearing
 

Easy to do or just get another alternator if necessary? Bought a stethoscope to use just to make sure the sound is coming from the alternator.

i would agree with first response,sounds like overheating worn out bearings,all you need to do is place a screw driver or wood dowel on it,then listen with your ear,you will hear the noise that does not sound right coming though the end.

Replacing Alternator
 

How difficult is it to replace the alternator? I have done it before on other cars but somehow this looks a bit more tricky with Mercedes. Am I being too concerned? Another recent poster said it took him 3.5 hours and sore arms! Should not be like that!