hosrom_951

It's been a while, but i thought it was normal.

I believe it's been going on ever since i placed thinner oil in the car (0w~40 Mobil 1)

If i floor it, i hear the turbo (that sssssssssssss sound) and once i let off the throttle/shift there is it wooooooooosh (just like a BOV). But i don't have a BOV.

Is this a sign of a failing turbo? do they get noisy on boost?

Oil consumption is ~average (accoriding to the manual 1L/1,000kms) when i get much more than that (~3,000-6000kms/liter depends how i drive the car)

No smoke on boost............no CAT, just a straight pipe..........but that sound wasn't there, started a few months back when changed the oil (but getting a tad louder these days).

Diver944

Has your throttle idle screw come loose from the top of the throttle body?

That makes a very prominent weeeee and whoooosh when it comes out

hosrom_951

Actually it's new and no it's fine, not loose

SamGrant951

I had that sound when I had a leak on the hose from the turbo-to-intercooler.

hosrom_951

The vacuum lines/pipe/hoses are all checked on.

But i am leaning towards the very thin oil that i am running that's causing this.

On boost, you can hear the turbo spinning, once you let go off the throttle, you can hear it stopping/slowing down (causing a woosh like a BOV).

DDP

Your impeller will not make any sound even when it is throwing itself apart.

Sami951

Oil shouldn't have anything to do with the sound. There has to be a leak of some kind, the stock intake system pretty much kills any and all induction noise.

If you have a cone filter in there you might hear something, and with a MAF or MAP system the whooosh will be definately audible.

hosrom_951

Gauge reads normal, no vacuum leaks...........started since using thinner oil..........

New DV, Vacuum lines, Boots etc.....

Sound is definately comming from the turbo area (could be the DV? but it's a few month old).........

Cyrus951

Oil doesn't have anything to do with it.
I had that exact sound when I had a leak on my IC pipe.

emwporsche

"Your impeller will not make any sound even when it is throwing itself apart."

compressor surge is very audible.
So yes, you can hear your turbo dying.

shortyboy

how about the bypass valve?maybe the diaphram is leaking?

hosrom_951

Its new.........

OIl consumption when off boost is great (almost zero) when pushing it REALLY hard for long times, it goes quick, so i don't think the turbo bearings are cooked. Using the turbo every now and then is fine, no oil consumption. But when using it alot (ie it gets hot) oil cnsumption is high.......

I am suspecting the blades failing, but why ONLY when i let off the throttle? on boost the turbo sounds normal.........

DDP

emwporsche...thanks for the correction, didnt think of that.

Eyal 951

Dear sir, I beg to differ... one of the worst sounds I have ever heard was VERY prominant as my turbo was self destructing.
~Eyal

hosrom_951

But why would the sound come on only when off throttle/shifting?

If the impeller blade was worn, it would be noisey at all times right?