Knowing proper turbocharger operation is very important with the different problems that can occur with your turbo, most avoidable.  Your Turbocharger can be damaged by dirt, ineffective oil, or heat due to improper shut down.  Most manufacturers recommend you to do more frequent oil changes when a turbo is installed and many manufacturers/owners recommend you to use synthetic oils which tend to flow more readily when cold and don't break down as quickly.

Many manufacturers/owners recommend allowing your engine to idle for one to three minutes before shutting down, due to the heat produced from the turbocharger, to prevent damage to the bearings when oil supply is cut off.  This period of idle allows the turbo to cool down with the lower temp. exhaust from the engine and still supplying oil to the turbo's turbine housing and exhaust manifold while still very hot.  If this cool down period is skipped "cooking" of the oil trapped in the unit can occur when the heat soaks into the bearings, which can cause rapid bearing wear and even failure when the engine is restarted.  Even small particles of burnt oil can accumulate and choke the oil supply and failure.  Although this problem is less pronounced in in diesel engines, due to there lower exhaust temperatures and generally slower engine speeds.

You can install a turbo timer to provide the cool down period needed for the turbo after each run.  A turbo timer will keep the engine running for a specific pre-specified period of time after you turn the key off and walk away. Another complex and sometimes problematic protection against oil cooking is the use of water cooled bearing cartridges.  Water is stored and boiled in the cartridge and when the engine shuts off it forms a natural recirculation to drain away heat from the turbo.  In custom applications the cool down period of the turbo is reduced with the utilization of tubular headers rather then cast iron manifolds, due to the fact that the lighter headers store much less heat than heavy cast iron manifolds.

Another thing to watch out for is the throttle increasing right before shutdown.  This can cause bearing damage and premature failure due to the turbo still spinning (much faster then would at idle) and oil pressure has dropped.

• Dirt, ineffective oil, and heat can damage your Turbo
• More frequent oil changes is recommended with the use of a Turbo
• Allow a 1-3 minute cool down period (engine at idle) after using your Turbo
• A Turbo Timer will provide the cool down period even if you turn off the key
• The Turbo cooldown period can be reduced with the use of different materials and/or parts