Turbo bypass valve

[Colin Hames]

The oil burning turned out to be the turbo.  I took the intake boot off and
spun the impeller by hand and felt a mild scraping noise and a little
resistence to rotate.  I have since removed it and sure enough there was a
bunch of oil gunk/sludge and nasty build up blown out the exhaust side.
Time for a rebuild.  The casings and impellers looked OK.

Thanks all for the input.

Colin


Colin Hames wrote:

> To all,
>
> I recently retrofitted my 5tqw with a turbo bypass valve or cut-off
> valve as Audi likes to call them.  I had a 1" metal tee welded
> perpendicular to the intake pipe half way from the air meter boot to the
> turbo inlet.
>
> I ran the car for a few days after the installation and everything
> seemed fine.  After letting the car sit for 2 weeks, I cranked it up
> last night for a quick run to the store ( 6 to 10 miles) and halfway
> there I had some serious problems.  I now have oil leaking from my
> distributor/hall sender and blue smoke drifting out the exhaust.
>
> Is it possible the bypass value is sent pressure back towards the air
> meter and through the vent hoses to the valve cover,  essentially
> pressurizing it and the crankcase, blowing valve stem seals, distributor
> seals, etc.
>
> Is the new issue just coincidental on a high mileage car? ( 160,000 )
> By the way, the car is completely stock.
>
> Colin Hames
> Minneapolis, MN
> '86 5tqw
> '90 200t