48450 Mercruiser PIN, Dowel

Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Dispose of all fluids according to local regulations and mandates.
Before you begin inspection of the turbocharger, be sure that the inlet air restriction is within the specifications for your engine. Be sure that the exhaust system restriction is within the specifications for your engine. Refer to Systems Operation, Testing, and Adjusting, "Air Inlet and Exhaust System - Inspect".The condition of the turbocharger will have definite effects on engine performance. Use the following inspections and procedures to determine the condition of the turbocharger.
Inspection of the compressor and the compressor housing
Inspection of the turbine wheel and the turbine housingInspection of the Compressor and the Compressor Housing
Illustration 1 g06411181
Typical example
(1) Turbine housing
(2) Compressor housing
(3) Ducts
Inspect the compressor wheel and the ducts for damage from a foreign object. The ducts can be removed. If there is damage, determine the source of the foreign object. Replace the turbocharger. If there is no damage, go to step 2.
Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The compressor wheel should not rub the compressor housing. The turbocharger must be replaced if the compressor wheel rubs the compressor wheel housing. If there is no rubbing or scraping, go to step 3.
Inspect the compressor and the compressor wheel housing for oil leakage. An oil leak from the compressor may deposit oil in the aftercooler. If oil is found in the aftercooler, then drain and clean the aftercooler.
Check the oil level in the crankcase. If the oil level is too high, adjust the oil level.
Inspect the engine air cleaner element. Replace a dirty engine air cleaner element with a clean engine air cleaner element. Refer to Operation and Maintenance Manual, "Engine Air Cleaner Element (Dual Element) - Replace" or Operation and Maintenance Manual, "Engine Air Cleaner Element (Single Element) - Replace" for the correct procedure. Inspect the engine air cleaner service indicator. Refer to Operation and Maintenance Manual, "Engine Air Cleaner Service Indicator - Inspect" for the correct procedure.
Inspect the engine crankcase breather. Clean the engine crankcase breather or replace the engine crankcase breather if the engine crankcase breather is plugged.
Remove the pipe for the oil drain. Inspect the drain opening. Inspect the oil drain line. Inspect the area between the bearings of the rotating assembly shaft. Look for oil sludge. Inspect the oil drain hole for oil sludge. Inspect the oil drain line for oil sludge in the drain line. If necessary, clean the oil drain line. Replace the oil drain line if there is any sign of damage to the oil drain line.
Inspect the back pressure valve for visual damage. Check that the exposed spring and lever mechanism is free from mud and debris. The operation of the back pressure valve can be checked by turning the keyswitch to the RUN position and then to the OFF position. This will drive the back pressure valve to the CLOSED position for approximately one second and return the back pressure valve to the OPEN position. This motion is visible from the exposed spring and lever mechanism.
If steps 3a through 3e did not reveal the source of the oil leakage, the turbocharger has internal damage. Replace the turbocharger.Inspection of the Turbine Wheel and the Turbine Housing
Remove the air piping from the turbine housing.
Inspect the turbine for damage by a foreign object. If there is damage, determine the source of the foreign object. Replace the turbocharger. If there is no damage, go to step 2.
Inspect the turbine wheel for the carbon and other foreign material. Inspect turbine housing (1) for carbon and foreign material. Replace the turbocharger, if necessary. If there is no buildup of carbon or foreign material, go to step 3.
Turn the rotating assembly by hand. While you turn the assembly, push the assembly sideways. The assembly should turn freely. The turbine wheel should not rub turbine wheel housing (1). Replace the turbocharger if turbine wheel rubs turbine housing (1). If there is no rubbing or scraping, go to step 4.
Inspect the turbine and turbine housing (1) for oil leakage. Inspect the turbine and turbine housing (1) for oil coking. Some oil coking may be cleaned. Heavy oil coking may require replacement of the turbocharger. If the oil is coming from the turbocharger center housing go to step 4a.
Remove the pipe for the oil drain. Inspect the drain opening. Inspect the area between the bearings of the rotating assembly shaft. Look for oil sludge. Inspect the oil drain hole for oil sludge. Inspect the oil drain line for oil sludge. If necessary, clean the drain line.
If crankcase pressure is high, or if the oil drain is restricted, pressure in the center housing may be greater than the pressure of turbine housing (1). Oil flow may be forced in the wrong direction and the oil may not drain. Check the crankcase pressure and correct any problems.
If the oil drain line is damaged, replace the oil drain line.
Check the routing of the oil drain line. Eliminate any sharp restrictive bends. Make sure that the oil drain line is not too close to the engine exhaust manifold.
If steps 4a through 4d did not reveal the source of the oil leakage, turbocharger (3) has internal damage. Replace the turbocharger.