I just switched out the radiator after noticing a crack on the top corner. Got it flushed and refilled it with straight MB coolant . But yesterday before taking it to the mechanics , I heard a high pitch whine coming from the timing belt area ,had it checked out and was told the belt looks pretty new and I'm guessing it could be the idler pulley and the tensioner . When I drive I hear basically a whistling noise that gets louder as I accelerate. At this point I'm not sure if it's the bearings in the pulley or what. No problems with car whatsoever prior .

The idler and tensioner pulleys are prone to failure. Try using a mechanic's stethoscope (carefully!) to isolate the noise.

ive ruled out the ac compressor because the ac still blows as it always has , cold and all. So il get the belt area checked again and post the results

having your AC compressor work perfectly is unrelated to the whining sound that it could potentially make. In almost all of the pulleys on the front belt are small ball bearing that break down over time, in some cases more then one set of ball bearing are in the component, such as the Alternator. Every component on the belt is a culprit. As Rudeny said you have to use a mechanic's stethoscope and pinpoint the issue. Most of the time a whining noise can be caused most by the alternator or AC compressor.

Makes sense , I appreciate the help . It seems to be coming from both sides , the alternator pulley and the ac compressor , when I put my ear close to one, you can hear the noise there , as well as the other side close to the compressor

An old shadetree mechanic's trick is to take an old garden hose and cut a length of it about 3 ft or so. Hold one end to your ear and probe around different areas that you suspect the noise is from. You will definitely hear the chance in pitch as you get near the bad part. It is a cheap stethoscope if you don't have one.

You don't get much cheaper than this:

http://www.harborfreight.com/mechani...ope-69913.html

It works quite well. Deafening, in fact, when tracing down suspension noises.

Realized that one of my pulleys isn't as quite aligned as the others, is there any way it can be realigned , or should it just be replaced . I would just like to know the risks , and what's the best step

exactly which one? most of them get changed if they are missaligned

Bottom right corner , closest to the ac compressor

There is no alignment for the belt pulleys.

Look here (bottom diagram with A/C):

http://benzbits.com/M112/BeltRouting.pdf

Which is it?

Well a couple of days ago I go to my mechanic so he can tell me what the problem really is , he said it was my compressor clutch , #2 in diagram given above. He said it was okay to drive for now and I pulled off , got a mile down the road and the power steering went out . I pulled right over parked it and took a look, the belt was split , and the pulley on the compressor was off, laying on the shield at the bottom . I'm guessing I need a new compressor. Does that mean I need a new condenser ?

I appreciate all of the helpful information

Replacing the compressor will also require a new dryer and a new expansion valve.