1981/03/06 Caterpillar

High Concentration Of Aluminum In Oil Analysis Can Be The Result Of Rocker Arm Support Wear


3208 Engines

A high concentration of aluminum in an engine oil analysis is not necessarily an indication of engine damage on 3208 Engines. The engine rocker arm assembly has thrust washers next to the aluminum support brackets which hold the rocker arm shaft. Normal contact of the thrust washers against the aluminum brackets during engine operation can wear away some of the aluminum from the brackets. This causes very small particles of aluminum in the engine oil, especially during the first several hours of operation of a new or rebuilt engine. The result is an indication of high aluminum content in an oil analysis.

Make a visual inspection of the oil filter elements to see if the high aluminum content comes from other sources, like pistons or bearings. The aluminum worn from the support brackets will not generally be visible in the oil filter elements.

Since the amount of aluminum worn from the brackets is very small, it will not cause engine damage if normal oil change recommendations are followed. The wear on the brackets will not have an effect on operation of the engine or valve mechanism, unless the brackets wear enough to permit contact between the rocker arms and the brackets. When the brackets become worn to a depth of approximately 0.89 ± 0.08 mm (.035 ± .003"), which is the thickness of one thrust washer, a second thrust washer can be installed to prevent rocker arm contact. When the brackets become worn to a depth of approximately 1.78 mm (.070 ") (the thickness of two thrust washers), install new shaft support brackets.

Caterpillar Information System:

1981/03/06 List Of Service Publications
1981/03/06 Changes Have Been Made To Caterpillar Service Literature
1981/02/04 New, One-piece Valve Lifter Used
1981/02/04 Inspection And Test Procedures To Follow When Fuel Ratio Control Does Not Operate Correctly
1981/02/04 Different O-ring Seal Now Used On The Oil Pump Suction Tube
1981/02/04 New Front Housing Assembly And Gaskets Used
1981/02/04 6V3150 Engine Pressure Group And 6V3121 Multitach Group Are Available For Testing Engines
1981/01/23 List Of Service Publications
1981/01/23 Purchase 3208 And 3406 Truck Engine Operation Guides, Parts Books And Service Manuals Directly From Caterpillar
1981/01/23 Wrong Turbocharger Group Shown In Parts Book
1981/01/23 Larger Plug Used In The Ends Of The Rocker Arm Shaft Assembly
1981/01/23 Two Replacement Lights Available For 5P7277 Voltage Tester
1981/03/06 New Turbocharger, Turbocharger Oil Lines Group And Aftercooler Air Lines Group Used
1981/03/06 Later Pistons Have A Smaller Number Of Drain Holes In Oil Ring Groove
1981/03/06 Modification Of Flywheel Prevents Loose Clutch Pilot Bearing
1981/03/06 Do Not Adjust The Fuel Setting Or High Idle Higher Than Necessary
1981/03/06 Two New Exhaust Manifolds Available For Replacement Of Single Rear Manifold To Prevent Broken Studs
1981/03/06 Check Oil Level Carefully To Prevent Operation With Too Much Oil In Engine Crankcase
1981/03/06 New O-ring Seal Used In Egr (exhaust Gas Recirculation) Control Has Better Resistance To Heat Damage
1981/03/06 New Governor Spring Available For Specific Engine Applications
1981/04/09 Low Engine Temperatures: Install Check Valve
1981/04/09 6V4163 Bit And 6V4164 Driver Now Available For Removal Of Bolts For Flyweight Carrier
1981/04/09 Correction To Torque Specification For Locknuts On Valve Clearance Adjustment Screws Of Engines Equipped With Jacobs Engine Brakes
1981/04/09 Special Studs And Nuts Available For Exhaust Manifolds On Engines Used In Heavy Load Conditions
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