The turbo on the 6.0 powerstroke turbo is a variable geometry turbo (VGT). What VGT does is actuate vanes that open and close to make your turbo a small and big turbo all in one. When the vanes are open it acts as a small turbo that can spool up faster. When the vanes are closed it acts like a big turbo for high boost. The only real problem that happens with these are the vanes get seized in one position. When this happens the turbo will stay only high or low. This will cause you to have a lot of turbo lag or will not have a lot of top end power. Cleaning the turbo is not a very expensive repair. Cleaning the turbo is a part of the bulletproof package. Another way to keep from having to repair the turbo is by not letting it set for very long and also just laying into the truck every once in a while to get it hot and clean it up a bit.
Signs of this are:
- Lots of turbo lag
- Loss of top end power
- At idle you will not hear the exhaust change tones