Diesel Engine - Crankshaft/Main Bearing Replacement
NUMBER: 09-003-06GROUP: Engine
DATE: February 25, 2006
SUBJECT:
Crankshaft Replacement Policy Change And Main Bearing Part Number Information
OVERVIEW:
This bulletin provides information to determine when to replace the crankshaft, which is a change in the "repair versus replacement" policy for Sprinter vehicles. Furthermore it provides a procedure to determine which main bearings shells to use when replacing the crankshaft.
MODELS:
2002 - 2006 (VA) Sprinter
DISCUSSION:
Repairing the engine with a new crankshaft is the preferred remedy when a complete engine assembly replacement is not required.
NOTE:
If the cost to repair the engine with a new crankshaft exceeds 70% of the cost to replace the engine assembly (parts with mark-up and labor), you must replace the assembly. This is commonly referred to as the "70% Rule".
NOTE:
The main bearings cannot be determined until the replacement crankshaft is received at the dealership. The markings on the front of the replacement crankshaft will dictate which main bearing part numbers to order for the main bearing caps.
The information outlined below describes how to determine which main bearing shells are needed for the crankshaft main bearings. The connecting rod bearings will always be the same size and part number.
PARTS DETERMINATION - MAIN BEARINGS:
^ The engine block and main bearing caps may have different bearing shell sizes, since each is determined independently.
^ The main bearing shell located in the engine block is determined by the markings on the engine block.
^ The main bearing shell located in the main bearing cap is determined by markings on front of the crankshaft.
^ There are 5 different main bearing shell part numbers. Each part number is a different thickness. Two of the part numbers can only be used for the main bearing cap.
^ The bearing shells are distinguished by reference colors, located on the back side of the bearing. Blue is the thinnest and violet is the thickest.
Determine the upper bearing shell, located in the engine block, for each individual main bearing journal by counting the number of punch marks, grouped for each main bearing journal, on the oil pan gasket surface of the engine block (Fig. 1).
Determine the lower bearing shell, located in the main bearing cap, for each individual main bearing journal by reading the letter, which is inscribed by laser at the front of the crankshaft. The string of letters is in the same order as the bearing journals; front to rear (Fig. 2).
NOTE:
Using the fifth main bearing as an example, the following information will demonstrate the process for determining the correct bearing.
EXAMPLE:
^ The upper bearing, located in the block, is determined by the two center punch marks in the block between the fourth and the fifth cylinder, see magnification (Fig. 1). The two center punch marks indicate that a bearing with a yellow mark on the back side, p/n 5102128AA, is required as shown in the table above.
^ The lower bearing, located in the main bearing cap, is determined by the "R" on the crankshaft, the fifth letter marking (Fig. 2). The "R" indicates that a bearing with a red mark on the back side, p/n 5102129AA, is required as shown in the table above.
POLICY:
Information Only
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.