Weird whining at crank, in neutral, and at throttle from the front of the car

[keithb123]

Hello Fellas! I am experiencing a weird problem :bigcry:. I have been hearing a whining noise (no blower) at crank, in neutral, and at throttle from the front of my 2004 MM. I have been hearing the noise for a few months and I thought it was cool at first (sounds like a blower) but recently it has gotten much louder. Initially, I thought it was the tension pulley since the belt had cracks so I replaced both. I cranked her up and behold ----- the same freaking noise. The sound is coming from the passenger side (A/C side) of the car. It sounds like it could be 1 of the 3 pulleys highlighted in the diagram.

Do anyone have any suggestions?




[04 MM, 120k miles, no probs other than tstat replaced]

[CBT]

With the car running, squirt WD-40 directly into the front of each pulley. If you blast one and the squeal goes away, disco! If not, try blasting it behind the pulley. I highly recommend spraying the WD-40 with the little red tube/spray nozzle or that stuff will get splattered around from your fan.

[Blackened300a]

The idler and the tensioner are very common to make noise on these engine and are cheap and easy to replace.
You can spray the idler all you want it won't change the noise. There is a washer that covers the bearing so you wont get any oil in there. The tensioner can be sprayed lightly and you can see if it changes tone.