Buzzing Noise AAZ vanagon

[stanton.samuel]

Hi,  I've got a loud buzzing noise going on here.   Only under load, only at high revs.  Doesn't make the noise at all in 1st, in 2nd only if i push hard to the two dots (stock diesel vanagon speedo) and then only when i'm getting up there in rpm) 3rd at about 40 if i push it (especially up a hill) and 4th up a hill above about 45-50 or constant above about 60 on the flat.  buzzing oscillates on and off at the edge and goes constant if i press harder on the pedal.  if i go back and rev it manually with the hatch open (i'm not brave enough to do this on the road, or at least not yet) I don't hear the buzzing if i rev it up the turbo waste gate operates at some point, but no buzzing...

i've looked for something loose or rubbing pretty much everywhere i can think of.

i've used the search.

suggestions?

thanks

[R.O.R-2.0]

exhaust rubbing somewhere? front trans mount wasted?

[vanagonturbo]

Exhaust is what I was thinking too..

[wdkingery]

the ford manual (hahah yeah really) says an oscillating noise is something that spins quickly in a circle that is unbalanced or has play.. and the sound is eminating from something that doesn't like this new vibration.
my pennies are in driveline.
if you can find a lift, get it up in the air and run it up to speed.. you might be able to see your problem doing it's wiggle
if you live in america, you can go to a firestone, and tell them you need to do a CVI (complete vehicle inspection) and that you need the friends and family discount (from $20 for a CVI to free in most cases) then manage to "wander" out to the vehicle while he's checkin your muffler bearings and convince someone to run it up to speed and have a look-see.

dubious but can be effected

[CRSMP5]

ill ask...

got a boost gauge?

boost controller?

my toaster has a odd buzz... right around 10-15psi.. boost controller set to 21psi at moment..

ive come to beleive its the boost controller internal dampner or a sound from the tubing running for said items..

its pretty odd.. but goes away if i have no boost..

[stanton.samuel]

i have a boost controller in the engine bay, no gauge, i've never adjusted the controller, it was put in with the engine. 

 what might happen if i delete it? i would guess i would have less boost? stock boost? the waste gate (thats what i'm calling the plastic valve on the intake manifold) dumps pressure if i rev it up manually above a certain point.

all i have for exhaust is a few elbows and a flexible steel section it doesn't rub against anything it just hangs off the turbo really 

neither of the axles coming off the transaxle had any play. when i tug on them.

the noise started shortly after a rear break rebuild... if that suggests anything.

what are the odds its a pump issue?

[tdihuntdawg]

a boost gauge would be handy for troubleshooting, if your controller is set higher than the stock blowoff it would be fluctuating in a weird way .I have seen intercooler boot with a broken clamp on a semi make a buzzing sound.plug the hose on blowoff to  test. pm me this weekend I have a billit. plug I not using . id like to compare Aaz vanagons

[stanton.samuel]

i havent had a chance to play with this at all lately (working too many hours and just riding the motorcycle because i'm scared to damage the van)  i'm thinking the stock blow off might be blowing off early and making the noise, i can't tell if i've lost some power or if i'm just afraid to use the pedal because i dont like the sound of it.  I'm in rhode island, how much for the block off plug?  I dont have any intercooler, but i'm gonna go look again for anything loose around the tranny and engine mounts and along the exhaust... though there isnt much to my exhaust   I've got a guy here (in Rhode Island) who is real good, but not real cheap... so i'll look a while longer before breaking out the credit card if i can

[Gizmoman]

I have an 82 Westy with a 1.9 AAZ TD and it started screaming (not buzzing) if I put my foot into it. It ended up being loose bolts on the turbo to the manifold and the noise was high pressure are squirting between the faces of the flanges. All three bolts were quite loose. Once tightened all was fine.

If I were in your shoes, I would spend some time just tightening up bolts, hose clamps, anything I could get to in the engine bay and underneath. You might be surprised what you'll find and the noise could even disappear as well.

[stanton.samuel]

I have spent some time at this now, i've found all sorts of loose things to tighten (no surprise) but noise is still there, i'll look closer at the turbo when its dry outside

[vanagonturbo]

Can you take a video?

[stanton.samuel]

I'll try to take one with my phone, nothing to see but the audio recording might be of some use.

[stanton.samuel]

http://youtu.be/UrxHCHtKWVg

youtube video from my phone,  i revved it higher than i usually do in 3rd because i was paying too much attention to the phone, but not too extreme.  you can hear the buzz pretty clearly when i give it throttle at high RPM, and lower RPM while going up hill.  i've trained myself to drive without making the noise, but that keeps me going pretty slow, anything above 50-55mph i can barely give it any throttle above just keeping steady speed without the buzzing.  I'm running an air cooled bus transaxle stock gearing (and forever wishing i had a custom 5 speed)

[vanagonturbo]

Sounds like a leak more than a buzz to me. Hard to tell though. Exhaust manifold tight to head? No leaky gaskets there? Turbo tight to manifold? Maybe a charge pressure leak from the turbo to the intake manifold?

[stanton.samuel]

that sounds reasonable to me... i think i may be entering the realm of needing to just take it down to my local VW guy, he's good, but not cheap.  so i usually try to trouble shoot myself first without hacking the old girl to pieces too much.  I'm still tempted to try and attach a piece of hose to the blow off valve and see if the noise changes indicating that is where its leaking.