MerCruiser Rear Oil Seal Service Procedures 5.0L 5.7L 6.2L

Rear oil seal service procedures for 2001 2002 2003 2004 2005 and 2006 MerCruisers. Note, procedures may differ depending on year and model. See repair manual for additional instructions and pictures for additional repair procedures.

Models Covered in This Manual

Sterndrive (MCM

5.0L MPI Alpha and Bravo

350 MAG MPI Alpha and Bravo

350 MAG MPI Alpha and Bravo Horizon

MX 6.2 MPI

MX 6.2 MPI Horizon

Inboard and Tow Sports (MIE)

350 MAG MPI Inboard

350 MAG MPI Horizon Inboard

MX 6.2 MPI Inboard

MX 6.2 MPI Horizon Inboard

350 MAG MPI Tow Sports

Rear Oil Seal

It is not necessary to remove the oil pan or rear main bearing cap from the motor when replacing the rear crankshaft oil seal. 

Removal

1. Take off the flywheel.
2. Take off the rear oil seal. You can use a screwdriver to or similar tool to pry out the rear oil seal from the seal retainer.

Cleaning

1. Clean off the crankshaft sealing area and mating surface.
2. Clean off the rear oil seal retainer bore.

Inspection

1. Check the seal retainer bore for chips or burrs. Use an emery cloth to remove any slight imperfections.
2. Check the crankshaft sealing surface for damage, this includes possible scoring, chips or burrs.
3. Check the outside diameter of the motor flywheel pilot flange or slight imperfections, rust or very minor surface corrosion. Very minor imperfections can be removed with a fine grade emery cloth.

Installation

Note: Use motor oil as the lubricant for the following:

1. Apply a small amount of lubrication to the bore of the rear oil seal retainer.
2. Apply a small amount of lubrication to the outside diameter of the flywheel pilot flange.
3. Apply a small amount of lubrication to the outside diameter of the flywheel locator pin.
4. Apply a small amount of lubrication to the outer diameter of the rear oil seal.
5. Take off the installation guide from the new crankshaft rear oil seal.
6. Apply a small amount of lubrication to the outside diameter of the new crankshaft rear oil seal.
7. Reinstall the new crankshaft rear oil seal on the seal installer.
8. Reinstall the rear oil seal installer on the rear crankshaft, then tighten the tool bolts until the come in contact.
9. Never allow any other forms of lubricant to come in contact to the seal surface on the rear oil seal.
10. Correct crankshaft rear oil seal alignment is very important. See repair manual for caution details.
11. Rotate the rear oil seal installer nut by turning counterclockwise to detach the rear oil seal installer from the rear oil seal.
12. Take off the rear oil seal installer from the crankshaft.
13. Clean away any excess motor oil with a clean shop rag.

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