What is this noise?
 

Hello,

So, my wife's car started sounding really rough and loud. It seems to be coming from the passenger side of the engine possibly around the serpentine belt? I initially thought it was the timing chain tensioner so I replaced that but no improvement. Could this be the supercharger or idler pulley or something else?

The car currently has 110,000 miles on it. It is has good power, the oil level is correct and it is not overheating. Around 85,000 miles I changed the oil in the supercharger as preventative maintenance. Any suggestions? I will attempt to attach a you tube video to assist.

I tried running the engine for a few seconds with the serpentine belt off and the engine sounded perfect! So that rules out the timing chain guide rails or anything internal. When I removed the belt I noticed that the DT Tensioner Stop was broken and the polyurethane bushings had rotted out (I think I installed these 2 years ago). One was completely gone. Hopefully this was it, but it is hard to imagine that this is what caused all that noise. I spun the other pullies by hand including the alternator and supercharger. Everything spun freely though I could hear a faint clicking in the supercharger. I don't know if that is normal or an indication that the problem is also in the supercharger. Anyone have any experience with this?

Hard to diagnose a noise without any kind of audio...without the serpentine belt attached you aren't spinning the supercharge or any of the accessories so there is no way to rule out any of them. Spinning freely by hand is a good thing but the RPMs at idle are pretty fast....so I'm not sure it is too representative..of any binding. What about the idler pulley?

don't quote me on this but it sounds like the bearings are all chewed up or going on their way out in your supercharger.... 99% sure that is the noise.

Did you ever figure this one out? I am getting the exact same noise on my 2006 MCS, and am searching for the fix before something really bad happens. 173K miles on the car.

noise
 

my noise is when I start the car and them 15 minutes later came back to normal. 33k mail and a 2010

Sounds like it's coming from the belt tensioner area. Could be bad damper bushings or just a bad tensioner.

I have really high doubts about it being the supercharge as it really sounds like it's coming from a pulley down there. Best thing to do for this kind of noise, go to your local part/tool shop and buy a mechanic stethoscope (long rod at the end of it). Put it against the alternator case, A/C compressor, ilder pulley, etc, and you'll be able to pinpoint the problem. Just need to be careful with the moving belt/pulleys. My 05 S suddenly developed a grinding metallic sound in april of 2013 and it was the alternator bearing eating itself.

check your crank pulley. common issue making noise similar to the chain tensioner noise.

So I installed a rebuilt supercharger and that solved the problem! Now it sounds better than new. It's interesting, I decided to change the oil pan gasket while I was there and discovered a pile of broken pieces from the timing chain rail. This obviously lead me to believe that my timing chain rail must be broken too. I removed the oil pump cover to get access to the chain and it turned out to be in perfect condition. The previous owner must have had the rail break on them and so they replaced it but neglected to clean out the broken pieces from the pan! I got this car when it only had 40,000 miles on it. That is pretty early for a something like that to happen.

When I went to start the car for the first time after reassembling it, I got power to all the instruments and lights but the car would not start. I could just hear the sound of the starter spinning but not connecting to the fly wheel. My first thought was that the starter solenoid had gone bad but I went back and checked all my fuses and connections I discovered I had just not tightened one of the earth straps down enough! It started right up after that and was a huge relief as I am sick of working on this car!

For the moment the car is working great, now I just have to sort out an airbag warning light that has been on for months. I think the sensor in the passenger seat has gone bad.
Any advice one that would be greatly appreciated!