Subaru B9 Tribeca SUV Forum banner

Don't you hate noises you can't identify???!!! 'Fluttering' noise. Assistance please.

574 Views 28 Replies 2 Participants Last post by  Flat6er
Hi friendly people!

I have what I would call a fluttering noise.


It only happens under load, driving, not when revving at idle.
Usually more pronounced accelerating from low speed, accelerating out of a corner for example.
Definitely a flutter-whine (if that makes sense), and doesn't sound like a 'rattle' to me

Higher speeds maybe does it slightly but hard to tell, might be drowned out by engine noise at higher speeds though.
Little hard to tell but I think it very very slightly interrupts power uptake (don't quote me on that)

I've changed serpentine belt, idler and tensioner pulleys. Could it be the actual whole serpentine belt tensioner assembly itself? Do these go bad?

Worried it might be the timing chain/timing chain tensioners. Please god no.

Thanks so much. Have a feeling it wont be cheap either way LOL

EDIT: i think my above statement is correct. I decided to drive in manual mode to see if it was possibly the transmission and it didn't do it at all on a 15km trip. Does this make it sound like torque converter or possibly a solenoid?
21 - 29 of 29 Posts
I think it is getting worse... but may be that is because it wasn't driven lately. Will drive it more to see how it goes... anyway - 1) wanna get to the bottom of VXDIAG thingie (will I be able to use it or not) 2) will replace solenoids in valve body... fingers crossed :D
Mines not worse but it's not better lol. I'm now getting an obvious 'tap' noise on light acceleration as whatever applies power. Stupid thing is from inside it sounds like it's coming from left side under the door area but when sticking my head under the bonnet sounded like throttle body. So cleaned MAP, throttle body (which was putrid) and even sprayed the PVC valve clean. No change to anything of course. Be nice if used parts were cheaper to replace throttle bottle but here in Oz not so much
I would guess - tensioners.... ;) (more ideas for you :D
Yeah I'm concerned it's timing belt tensioners since I've changed serpentine belt and pulleys. Small chance it's the whole belt tensioner assembly but need to change it to be sure, but if doesn't sound like it's coming from there. Not sure I want to do chain and tensioners, maybe just the tensioners if I do but is it worth doing half the job and not changing the chain? Plus it looks like it's not actually difficult but all the vids I've seen are with the engine out already
there is no timing belt - chain is ;)
and those tensioners and chain are underneath front metallic cover :)
p.s. another source of noise - AVCS and their solenoids?
Sorry I meant timing chain. I'm tempted to do it all but need to look into it, doesn't look complicated if you take your time, but since I've never seen a YouTube video doing it with engine in car I'm thinking it might be a nightmare.
I would start with FSM, not youtubers... though MrSubaru1387 might have something for ya :D
Even with new idler and tensioner pulley, and the new belt, it still made a serpentine belt noise starting up the other day. Question. Am I correct in assuming because the belt goes around the crankshaft pulley that it is rotating at the same rate at any one particular rev range? Ie at 2000rpm it's always rotating at the same rate? So my noise etc could still be tensioner related? For example the actual tensioner assembly itself? Or maybe another pulley at a certain rpm?
what about bearings in alternator, a/c compressor? or powersteering pump? ;)
all the pulleys are different size, so... when crankshaft rotates 2k rpm - they don't.
21 - 29 of 29 Posts