Langdon Posted June 12, 2005 Share Posted June 12, 2005 To the mechanically inclined, from a first-time Subaru owner: My 2001 Outback's engine produces an odd 'buzzing' or vibration sound when the RPMs reach 27,000 to 30,000 RPM. This happens either driving down the road or when simply revving the engine in neutral. It is a rapid, metallic rattling heard on top of the regular sound of the engine, and subsides above ~30k RPM. I don't hear it when the windows are up and the mechanic who looked the Outback over before I bought it last week didn't see anything wrong. There seems to be no loss in performance, but it definitely sounds like there's something wrong. But then again, this is my first Subaru. Any ideas what this sound could mean? Quote Link to comment Share on other sites More sharing options...
Olnick Posted June 12, 2005 Share Posted June 12, 2005 Easy answer. It's the sound of your pistons and small pieces of engine flying by you! Sorry Langdon, couldn't resist that one. Check your rpm numbers--I think you've got one too many zeros in there! Seriously, since the sound happens in such a specific range it could be as simple as some kind of harmonic or resonance causing a heat shield on your exhaust to vibrate. Can you somehow identify the location of the buzz--maybe have someone hold the rpms steady while you listen around the car? If the car seems to run smoothly it's probably not life threatening. Good luck. Quote Link to comment Share on other sites More sharing options...
Dr. RX Posted June 12, 2005 Share Posted June 12, 2005 WOW, your engine will turn that high, I have never had mine above 8,000 RPM. Quote Link to comment Share on other sites More sharing options...
outback_97 Posted June 12, 2005 Share Posted June 12, 2005 I was gonna say the same thing as Olnick But seriously, a second vote for possible heat shield. A common thing for Subies, mine sometimes buzzes or rattles at specific RPM's, our old GL did too. Steve Quote Link to comment Share on other sites More sharing options...
Langdon Posted June 12, 2005 Author Share Posted June 12, 2005 Whar har har. Yeah, silly me. Funny how a zero can mean so much. I'll get someone to help me try to isolate that noise, though. I just wanted to make sure it wasn't a commonly known problem that would eventually cause my outback to drop its transmission or burst into flames. My big issue is that it makes my car sound like that car that that other guy always drives... The guy with the squeaky brakes. I know you can sympathize with that! Quote Link to comment Share on other sites More sharing options...
unverviking Posted June 12, 2005 Share Posted June 12, 2005 Just did the hose clamp fix it on 1 of the heat shields on 1 of the cats. Fixed it nicely... Just waiting for the "next one" Quote Link to comment Share on other sites More sharing options...
Olnick Posted June 12, 2005 Share Posted June 12, 2005 Whar har har. Yeah, silly me. Funny how a zero can mean so much. Ah, it's nothing! Quote Link to comment Share on other sites More sharing options...
subiefan Posted June 13, 2005 Share Posted June 13, 2005 Sounds like a heat shield somewhere to me. Mine does the same thing only in the lower rpms, usually around idle. Anyway, sounds like a rattling heat shield is causing your trouble. Quote Link to comment Share on other sites More sharing options...
Langdon Posted June 13, 2005 Author Share Posted June 13, 2005 Heat shield, eh? I'll check it out and keep this thread posted. Thanks a lot! Quote Link to comment Share on other sites More sharing options...
Andyjo Posted June 13, 2005 Share Posted June 13, 2005 at around 10k RPM your pistions will start to shoot out of the block, and since they're horizantally opposed.. they'll most likely take out your front end, wheels, etc. So i believe that a 'humming' or 'buzzing' would be normal at that kind of speed =p But yeah, the heat shields on my headers likes to do that., also if you've ever high centered it check in the middle, sometimes the heat shields get bent up and touch the exhaust. Quote Link to comment Share on other sites More sharing options...
philip Posted July 11, 2005 Share Posted July 11, 2005 This may or may not be related, but I just bought a 2001 Subaru LL Bean w/ 64K miles. Very nice ride, overall, though I have noticed two weird noises. First, when accelerating on the hwy 70-80mph (with stereo OFF) I hear a high frequency noise that sounds electrical, ie., I think it's too high a frequency to be the tranny or the engine. Then when I take my foot off the accelerator and coast through 65-60mph, I hear a vibration from somewher up front, sounding a bit like a rattle or a mechanical resonance. Neither noise seems to affect performance, though I wonder about long-term negative effects. Any others out there have the same experience? If so, any insight into causes and solutions (besides turning the stereo back up)? If the heatshield fix could be it, where is the heat shield? Note that the two sounds are different in frequency (a whirr vs. a rattle). Quote Link to comment Share on other sites More sharing options...
Langdon Posted August 17, 2005 Author Share Posted August 17, 2005 Update! I finally took my OB to the shop for a $1600 fandango of maintenence, and the shop isolated the rattle to the heat shield on one spur of the Y-pipe under the engine. My mechanic said it would be okay to remove the rusted shield, so I gave my consent. It turns out he removed the entire heat shield from the Y-pipe, not just the rattling segment. The car sound great now, I'm just wondering: Do you really think I'm okay without that heat shield? And would the heat shield otherwise act as a rock-guard against the perforation of the Y-pipe? Quote Link to comment Share on other sites More sharing options...
1 Lucky Texan Posted August 17, 2005 Share Posted August 17, 2005 Update! I finally took my OB to the shop for a $1600 fandango of maintenence, and the shop isolated the rattle to the heat shield on one spur of the Y-pipe under the engine. My mechanic said it would be okay to remove the rusted shield, so I gave my consent. It turns out he removed the entire heat shield from the Y-pipe, not just the rattling segment. The car sound great now, I'm just wondering: Do you really think I'm okay without that heat shield? And would the heat shield otherwise act as a rock-guard against the perforation of the Y-pipe? Doubtful it's a problem - but be aware there is a slightly greater chance of strating a grass fire if you immediately pulled off the freeway and parked on top of tall, dry weeds or something. (my oldest daughter lives in the springs) Carl Quote Link to comment Share on other sites More sharing options...
mtsmiths Posted August 17, 2005 Share Posted August 17, 2005 Plus, when you park in fresh snow, you get this great schematic of your exhaust system on the ground when you pull away again. Quote Link to comment Share on other sites More sharing options...
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