Tonight was another in a string of unpleasant surprises...

From the beginning:
Around New Years a loud, RPM-dependent hum/groan started, emanating up from below the intercooler. Identical to sound in this video:

My assumption was a supercharger bearing, which was backed up by the dealer service writer that listened to it. He quoted me ~$4k to fix
Decided to save the cash and fix it myself. I'd had the S/C out about two years ago to do the oil service so I knew I could handle it.

Sent the blower to autoxcooper for rebuild. Got it back about 3 weeks later, opened up the box, discovered oil-soaked cardboard from leaking PTO 'box. Sent it back again, received it about a week later, oil leak solved.

Finished buttoning the car back up tonight, start it up and...
SAME NOISE

Just to be sure I took the belt off and started it momentarily - noise gone. I can't imagine it's from any of the other pulleys (alt, A/C, idler), but is there any way to test?

I'm pretty deflated right now and wondering what to do next. Going to call Dustin at autoxcooper in the morning. Just thought I'd come on here to vent since you're such good listeners and always willing to help.

 

.... uh.... I'm not hearing anything in that video (other than a really loud intake woosh lol) is it the squeak squeak squeak you're hearing?

anyone else?

Perhaps consider trying the timing chain tensioner:


and/or PVC valve? Both are "cheap" and very quick.

I'd get out the stethoscope to keep looking for the location. As I understand it, the PTO failure sounds like a bunch of marbles running amok in your engine bay.

Something more like:

 

If they noise goes away when you take the belt off doesn't it have to be one of the pulleys the belt goes around?

Did you spin or check the pulleys after you took the belt off? With all that noise I would think the bad one would be noticeable when you move it by hand. Maybe not though.

On a side note did you pop the cover off the sc to check the water pump gears before you sent it in? Was there any oil left in it?

I would be concerned about the leaking cover. What kind of half assed job did they do?? That cover should hold oil for many many years no matter what position it ended up in during shipping.

Despite the bad service, I wouldn't automatically assume it's the sc making all that noise . I made the same mistake after getting mine rebuilt (no oil left in mine) It made a bunch of noise after putting on the rebuilt sc on and it turned out to be the tensioner pulley. Different sound than yours though.

 

Did you replace the water pump? It is in the area you said and is driven off the SC pulley

 

Do this....
Sit down in the car...start it....or have a partner do it...
Have them press in the clutch... See if the sound changes....if it does, it's the throwout bearing....
If it does not..next step...
I would turn off the car...REMOVE the BELT...you will not have a water pump, but it will run (you might need to have the IC off, the only time I did this it was off, so not sure) you will get codes, but just clear them with a odb2 scanner when done). You will be fine for a minute or two before it gets too hot, more than enough to check for a noise.
Start the car for a minute or two...if you don't hear the noise, it is one of the items attached to the belt...STILL HEAR IT, it is internal, a lifter or possibly a cam issue, or other bearing issue.
Good luck

 

Sorry to leave you all hanging. Thanks for all the suggestions, I should have time do further diagnosis this weekend.
Meantime, here's a bit more info:
The water pump was changed 20k ago when I performed the S/C oil service and the car never had an overheating problem before the noise developed. The shop that rebuilt the S/C said the gears were fine and that the only problem noted was the rotors rubbing the front of the case, to which they attributed the noise I described.
When I started it without the belt the noise was not present but the car quickly died (because I left the IC on and the S/C wasn't driven). I did a quick check on the other pulleys and none seem to have any bearing play or grittiness, nor does the belt move side when turning. The idler pulley is 20k old and the tensioner is brand new after the last one had the damper fail at 20k. Wondering if a problem with another pulley could've been a factor in the tensioner dying so quickly.
Next I plan to go at it with a stethoscope and also check the throwout bearing as Zippy recommended. Right now though I suspect the harmonic damper or possibly, though less likely, the alternator.
Thanks again for advice and I will update hopefully soon.

 

Not sure how the to bearing is related to the noise going away with the belt off but whatever. Maybe you have multiple noises.

The main problem seems to be the sc.
You sent it to the shop twice, and they think the rotor is rubbing the front of the case and making the noise.

Why didn't they fix it the first time? Or the second time?
What in the world is going on with that shop?

That's some crazy bad service if that's where the noise is actually coming from. What exactly did they claim to do to it?

 

Also check out the alternator and aircon compressor. They can make the growling bearing noise on the way out too. If the noise stops when the air on comes on it is the clutch on the ac compressor, AFAIK it is change out the compressor. Alternator should spin by hand, best to stethoscope it at hand turning speeds.

James

 

There are some good suggestions above. One note: when pinpointing the source of the noise, you might be better off using a long prybar instead of a stethoscope. Stethoscopes are too sensitive for these noisy motors. Put your ear on the end of the handle and the tip on the nose of the supercharger, tail of the supercharger, water pump, and other accessories. It takes a little experience to know what's a good and a bad noise. If you have a friend with a R53, listen to theirs for comparison. Good luck.

 

I recently replaced the idler pulley, which took all of 15 minutes. It sounded like a power steering whine and got louder when applying throttle. I too thought it was the supercharger, but a $5 stethoscope from harbor freight zeroed in on it being the pulley. Get a stethoscope, and put the end on the head of the bolt, you should hear a grinding/moaning noise.

 

Well I learned a harsh lesson in diagnosis - always get a second opinion!
Yesterday the patient was examined using the harbor freight stethoscope and found to have healthy-sounding lungs (S/C) but a screaming alternator bearing. Whoops
That's on me for taking someone else's word for it and not recognizing my own biases in the matter. So I'm out about 1200 for the apparently unnecessary S/C rebuild and several months of downtime (which honestly hurts more than the money since every blower will need to be rebuilt eventually, guess I just did mine preemptively, at least that's what I'm telling myself to cope).
Anyway I learned a lot along the way with this repair and also used the time to install some other nice mods (full exhaust, short shifter, poly bushings and engine mounts) so once the alternator is taken care of I'll just enjoy the car that much more and forget about this charlie foxtrot I made for myself.

 

Wanted to followup also and say a big thank you to everyone who chimed in on this thread with great advice. I really appreciate the NAM community in general and you all in particular.

 

sorry about your loss, glad you've got a great attitude about it.

Trust me when I say that a $1200 Charlie Foxtrot was nothing like my $16,000 one. You got off easy.

Now, just keep checking the engine oil EVERY time you fill up for a number of months until you know how much the engine consumes oil, or you'll be getting into my territory.

Happy Motoring!