Maintenance Procedures

The turbocharger system requires no scheduled maintenance, however, the engine oil must be changed more frequently than a non-turbocharged engine. For service intervals, refer to Maintenance Schedules, Indicators and Service Procedures.


Good maintenance practices must be followed to maintain the service life and performance of the turbocharger. Turbocharger failures are most often caused by oil lag, restriction or lack of oil flow, dirty oil, or foreign objects entering the turbocharger.


1. Do not allow dust, sand or other foreign material to enter the turbocharger. Dust or sand entering the compressor housing from a leaky air inlet system can erode the compressor wheel blades. Uneven blade wear can produce shaft motion that can cause bearing failure. Dust and sand also wears engine parts. Large or heavy objects will completely destroy the turbocharger and may cause severe damage to the engine. Soft materials, such as towels or rubber items, will roll the blades backward. If a turbocharger fails due to foreign material, a thorough cleaning of the air and exhaust system is necessary. No foreign objects should be in the plumbing, and all connections must be secure.

2. The air system must be properly maintained. A plugged or restricted air cleaner system will reduce air pressure and volume at the compressor air inlet. The air pressure drop will lower turbocharger performance and can cause oil pullover during idle. Oil pullover is a compressor end oil seal leak without seal part failure.

3. The lube oil system must be properly serviced. When dirt or foreign material is introduced into the turbocharger bearing system by lube oil, the center housing bearing bore surfaces will wear. Contaminants act as an abrasive cutting tool and eventually wear through the bearing surfaces. When bearing and bore wear become excessive, the shaft hub and wheels may rub in the housings. The rubbing will cause the assembly to turn more slowly than it should, and turbocharger and engine performance will rapidly deteriorate. Excessive noise or smoke and oil at either end of the turbocharger may be noted. Oil contamination must be corrected before a new turbocharger is installed. Do not assume that the oil filter will remove contaminants before they reach the turbocharger. Oil will completely bypass the oil filter if the filter is clogged, the bypass valve is open or the filter element is ruptured or improperly installed.

4. Do not allow sludge to build up in the turbocharger. Sludge accumulates in engine oil when oil oxidation or breakdown occur. Primary causes are engine overheating, excessive combustion products from piston blow-by, non-compatible oils, engine coolant leakage into the oil, incorrect grade or quality of oil and improper oil change intervals. When the turbocharger shaft spins, oil is thrown against the center housing inner walls. Any sludge particles in the oil will stick to the walls. Sludge deposits at the turbine end may become baked, or coked. The hard coke can flake off and wear the turbine end journal and bearing and bore, but usually the turbine seal will leak first. If turbine end oil leakage is noted, check the turbocharger oil drain tube and crankcase breathers. Remove any restrictions and check for sludge buildup on the shaft between bearing journals and in the center housing. Correct as necessary. If sludge deposits are found, the engine oil and filter must be changed.

5. Never operate the turbocharger under engine load conditions with less than 207 kPa (30 psi) oil pressure. Oil pressure and flow lag during engine starting can cause damage to the turbocharger bearings. Oil lag most often occurs after the engine oil and filter are changed, if the engine has not been operated for a long time, or when cold weather causes the oil to congeal. When changing the engine oil filter, prime the new filter with clean engine oil before installation. The turbocharger also must be primed whenever oil lag is possible and after every oil change. Before allowing the engine to start, disable the ignition system and crank the engine until steady oil pressure is observed. Enable the ignition system, start the engine and run at idle. Turbocharger bearing damage can occur if oil lag exceeds 30 seconds, sooner if the engine accelerates beyond low idle speed.