SwedeSpeed - Volvo Performance Forum banner

Anyone have any idea what this noise is? I have a sinking feeling it's an expensive noise.

6K views 23 replies 12 participants last post by  Hounddogger 
#1 ·
So my 6 months of R ownership have so far been cost free aside from a hose clamp and an oil change. I knew that wasn't gonna last with a 280k mile car, even one with receipts from mile 0,(I knew what I was getting into). Next week I have to do struts and tires...

However one issue has been masked until now. Ever since I got the car the cooling fan has run full tilt... A few weeks ago I got tired of it so I reset the ECM and on startup I can now hear a suspicious noise during the cat heatup high RPM thing. It sounds like flywheel noise because the car is is neutral. Is the DMF failing?

Here's a video:

 
#3 ·
So it's metallic for sure, I bet either something pully related (Alt, tensioner, etc) or it even sounds like a turbo fin grinding but I highly doubt that unless your turbo is really off an has a lot of play + smoke.
 
#4 ·
It's just a heat shield or bracket rattle. The Higher RPMs on cold-start hit the right frequency to make it rattle, then when the RPMs drop the rattle subsides/diminishes. Have a friend start it cold whil you stabd in front with the hood open.
 
#7 ·
I agree with this. Park it on ramps or jack stands one night and upon cold start next morning get your ear closer. That's a pretty loud rattle and shouldn't take too long to at least narrow it down to a compartment of the engine.

Is it just as loud on the passenger side? Maybe something with the downpipe or cat back rubbing in the tunnel? Turbo heatshield loose? It just sound like a harmless rattle base on the video.
 
#8 ·
Sound like the alternator, mine made that noise last week...
 
#9 ·
I'm going with alternator on this one, as well. Not my R, but my Audi's alternator is making this noise. The bearings in mine are shot.
 
#10 ·
If it were the alternator or another accessory component and a bearing was failing, the noise wouldn't go away when the RPMs drop. Change yes, but not go away. Still, without a better open-hood video or seeing the car in person, anything's possible.
 
#12 ·
Does your A/C work? Cooling fan on full tilt is either a software glitch (but only on 2006's apparently and accompanied by a non-responsive temp gauge) or it can happen when you have no coolant in your A/C system.

Leads me to think those saying A/C compressor may be on to something, as much as it sounds like just a loose heat shield or piece of metal. Could be two totally separate issues as well.
 
#15 ·
Find a 3' or so 1/2" ish dowel rod or similar and carefully and securely place it on a component with the engine running. Making sure you are set and the rod is not in the path of the fan, put your ear on the rod. A bad bearing in an alternator will sounds like a metalic hell. Move the rod around the engine and isolate your problem. I have isolated dozens of alternators from AC compressors from water pumps from idler pulleys over the years with the old skool trick. Careful!!
 
#17 ·
Watching your first vid again with your new one.... Three guesses in no particular order
1. Brake dust shield on LF wheel
2. Bracket(s) for the airbox
3. Bracket for Brake vacuum pump
 
#19 ·
I think it's turbo related. When I turn my caR off, I hear the turbo compressor wheel slow to a stop and it sounds kinda like that but not anywhere as loud or metallic; mine has 250000 less miles on the turbo/engine though. I do have the hood blanket, airbox cover and engine-bae weatherstrip taken OFF as well
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top