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:???: Help! I was visiting my friend this weekend and she had me listen to her passat, when you let off the gas while driving it makes spinning noise off throttle. It sounds like that damn eclipse from F&F but I know what a turbo sounds like and my 2003 doesnt make this sound. It does not do it while in park when the engine is reved. Now, Here is my hypothesis, The bearings in the turbo are going. I belive this is a result of the VW dealer not putting oil back in her car after an oil change and that she possibly burned out the turbo or damaged it while driving it without oil. I have been thinking that it could be her diverter valve going but I have no idea what that would sound like. So does anyone have ideas? she has a 99 with 50,000 miles. The VW dealer said it was fluid or some BS. Also does anyone know of a good tuner/responciple dealer in the Raleigh/Durham NC area?
 

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How many miles did she drive after the dealer didn't fill her oil after the oil change? Was it not filled at all, or not filled to proper level? No oil can damage many things. :shock:
 

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Socrates42 said:
I belive this is a result of the VW dealer not putting oil back in her car after an oil change and that she possibly burned out the turbo or damaged it while driving it without oil.
Do you know that this happened or are you just guessing? If she operated the engine without oil in it she should get a written statement from the dealer that they'll fully cover any repairs that could have been caused by this event (if they made the mistake of not re-filling it after an oil change).

There is a sound that matches your description that is normal for chipped Passats and happens to a much smaller degree in stock Passats. It's the diverter valve "blowing off". The reason it doesn't happen in neutral is that without a load on the engine your turbo doesn't spool up and create pressure so when you chop the throttle there is no pressure being released, thus no blow-off sound.
 

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I know for a fact that they did not put oil in her engine, and that she drove atleast home and back without oil. She did get a statement from VW saying that the forgot to put oil in it. That was close to 3 years ago however. Her car is completely stock. That diverter valve "blowing off" is that because it needs to be replaced? Would a new stock unit, or a audi TT unit possibly fix this problem? If so it would be a much cheaper alterantive than replacing the turbo, Even though she has that letter I dont believe that VW would replace it after this ammount of time.
 

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It sounds more like a leak in the vacuum hose that goes from the divertor valve outlet to the turbo inlet (making the dv fuction just like an atmospheric blow off valve). The blow off valve has 3 hoses attached to it, high pressure from turbo, pressure in intake manifold (after throttle), return line to turbo inlet (after MAF). For that FF sound, a good leak in the hose from the return line to turbo inlet would do the trick!

If the bearings were destroyed in the turbo, you would hear some nasty screeching noises at WOT under boost, but they would go away when you took your foot off the gas. Also, you would definately experience low boost, low power and probably oil leakage (blue smoke) once the bearing was destroyed enough to allow the ring seals to get hit, eventually (short period of time, <5000 miles i'd expect) the turbo would sieze, ooze oil into the engine and you'd have a nice naturally aspirated engine that puts out a smoke screen behind it.

fyi-I work for Garrett Turbochargers as a Product Development Engineer, so this is right up my alley!
 

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If you are looking for a responsible dealer, Leith VW in Cary is not terriable, and certainly must better than the disaster zone that is Southern States VW of Raleigh/Durham.

SirWired
 

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Discussion Starter #8
Thanks for the info on the dealers, anyone know of a good tuning shop who might be able to give a second opinion on this? In the area that is...

oh and thanks passatX I think im gonna recomend that she replace the DV and see if that fixes the problem...
 

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my freinds passat did that he broke his by pass valve and it was leaking ait so it sounded like a sanke rattle. funny u ask just yesterday his boost cntroller said his car was runnin vaccum 10 he lost all pressure. luckly vw repaired it under warranty. take it in soon
 

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home AND back with no oil? does she live 2 feet away?
Modern engines would have siezed up before it got out the shops door

perhaps low enough to be off the dipstick, but certainly no oil whatsoever?!
 
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