There are five reasons why a turbocharger will quit performing.
1. Lack of lubrication.
2. Foreign material in the exhaust or inlet air supply.
3. Contaminated lube oil.
4. Defects in manufacture/workmanship.
5. Operating outside of design speed range. If any of the above situations occur prior to replacement, the main reason for deterioration must be fully understood and the condition corrected.
Failure to correct any of these reasons for turbo charger failure will result in repeated occurrences. Turbochargers will operate for many trouble free hours or miles without any major wear or deterioration occurring, providing good, clean air and lubrication are supplied to the turbocharger. Clean air and lubrication are the two items that have always provided for long engine life. Assuring yourself that these two systems are being maintained will be beneficial in the extended operation of turbo charged diesel engines.
Experience has indicated that if the turbocharger becomes inoperative due to lack of lubrication, diluted lubrication or contaminated lubrication or from foreign objects on either side of the turbocharger, very few parts can be reused. Any parts being considered for reuse should be properly inspected, using procedures outlined in Detroit Diesel service manuals or turbocharger manufacturer’s recommendations.
Turbochargers generate high operating temperatures and speeds which could cause personal injury. Also, there are high pressures at the com pressor outlet and a high vacuum at compressor inlet.
Operation of the turbocharger without all normally installed inlet piping and filters, along with exhaust piping, can result in injury to personnel and damage to equipment from foreign objects entering the turbocharger.
If operation of the turbocharger is necessary for tune-up without normal piping, use Turbocharger Air Inlet Shield J-26554A. Some turbochargers are equiped with permanently installed shield that should never be removed. (Obtainable from Detroit Diesel authorized outlet.)
Engine oil pressure provides lubrication and cooling to the rotating components of the turbocharger. If oil pressure for any reason is lost or restricted, serious damage will occur immediately to the shaft and full floating bearing.
If oil gage pressure is lost or oil warning light comes on, shut down the engine as soon as possible. On most applications, oil pressure is supplied with an external oil line from the main oil gallery and returned to the crankcase in the same manner. Some turbocharged engines return oil to the crankcase via a cast-in return passage in the adaptor that the turbocharger is mounted on. It is important that this return oil flows freely to prevent overheating of the turbocharger.
When an engine operating under full load is shut down without a short idle period, the heat of operation is not dissipated and all parts remain extremely hot. Oil films can be destroyed under this condition and, when the engine is started, considerable wear can take place before lubrication is sufficient. Extreme heat in the turbocharger can warp shafts and bores, making repair difficult. The bearings in the turbocharger are especially likely to be damaged.