[copbait73]

I have 36 years in turbochargers with Garrett and Schwitzer (now Borg Warner/KKK).

Here is a percentage to keep in the back of your mind. With passenger cars, 70-85% of turbo removals the turbo is not at fault. The aftermarket turbo business thrives on this, meaning they will gladly sell you a replacement or rebuild yours because by percentage the core you have is perfectly acceptable to place right back on your car. Usually if your turbo is truly FAILED they will give you a token core value then sell you a replacement (not rebuild yours) or UPGRADE.

I’ve instructed a 4 hour course on turbo systems and turbocharger specific fault diagnosis. It goes into great detail to fill the time and review almost everything under the sun. In the last 5 minutes I usually pull out a small mag flashlight and flat screwdriver and inform them we could have saved several hours by explaining the following:
90% of all true turbo failures can be quickly and easily detected by:
1. Using the screwdriver, remove the compressor inlet boot (usually very accessible).
2. Point the flashlight at the outer edge of the compressor blade. If you detect the blade is rubbing the housing the turbo needs replacement.
3. That’s it.

I won’t get into specifics expect to say there is a lot of talk about oil seals leaking. The “oil seals” everyone talks about are a combination of dynamic (flingers) and small piston ring gas seals. The point being they are not oil seals in the first place. If a condition exists for them to leak the causes are in descending order:
1. Restricted air-cleaner (dirty, oil contaminated, consumer/aftermarket mod related)
2. Engine crankcase pressure is too high (failed cylinder components, consumer/aftermarket modified breather system).
3. Oil drainage is inadequate (engine component or aftermarket mod related)
4. Turbocharger bearing failure (see above)

Hope this summarizes much of the anecdotal information.