ARMY TM 9-2815-255-24 AIR FORCE TO 38G1-95-2 MARINE CORPS TM 2815-24/4 b. Mark findings on checklist and continue inspection. NOTE You will need a good light source for this check. c. Check compressor inlet for wheel rub on housing.  Look very closely for any score marks on the housing itself and check tips of the compressor wheel blades for damage. 3-13.2.3  Compressor Housing Outlet. a. Check compressor housing outlet.  Outlet should be clean and free of dirt or oil. b. Mark it on checklist if dirt or oil is found and continue inspection. 3-13.2.4  Turbine Housing Inlet. a. Check turbine housing inlet ports for oil in housing, excessive carbon deposit, or erosion of center walls. NOTE If inlet is wet with oil, or has excessive carbon deposits, an engine problem is likely.  Center wall erosion (cracking or missing pieces), indicates excessive exhaust temperature. b. Record defects on checklist and continue inspection. 3-13.2.5  Turbine Housing Outlet and Turbine Wheel. a. Use a flashlight to look up inside turbine housing outlet and check blades for foreign object damage. b. Note any damage on checklist because inspection of the engine will be required. c. Inspect  wheel  blades  and  housing  for  evidence  of  wheel  rub.    wheel  rub  can  bend  the  tips  of  the  blades  with housing showing wear or damage. d. Note any excessive oil or carbon build-up on checklist. 3-13.2.6  External Center Housing and Joints. Visually check outside of center housing, all connections to compressor, and turbine housing for oil. NOTE If oil is present, make sure it is not coming from a leak at the oil supply or return line. 3-13.2.7  Internal Center Housing. a. Using a flashlight, look through oil return hole to check condition of shaft and/or bearings.  There should not be excess carbon deposits on shaft or in housing. b. Excessive 'blueing" or "coking" of oil along the complete length of shaft indicates a possible lack of lubrication caused by an engine failure, or improper operation, such as hot shutdowns. 3-13.2.8  Turbo Bench Test. a. Mount turbocharger in a vise. b. Rotate shaft, using both hands, to check rotation and clearance.  Shaft should turn freely, however, there may be a slight amount of drag. c. Next, pull up on the compressor end of shaft and press down on the turbine end while rotating shaft.  Neither compressor wheel nor turbine wheel should contact housing at any point. 3-48