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Title : Sealing Oil from the Crankshaft Gear on S13 Engines
Applies To : MY2023, MY2024, MY2025, MY2026 All S13 Engines

CHANGE LOG
Please refer to the change log text box below for recent changes to this article:
04/30/2026 - Initial Article Release

DESCRIPTION
This document provides instructions for sealing oil leakage past the flywheel bolt holes on S13 engines. Oil leaking from behind
the crankshaft gear may exit through the flywheel bolt holes and is often misdiagnosed as a rear crankshaft seal leak. This
condition is confirmed by oil-saturated flywheel bolts and visible oil pooling in the flywheel bolt holes behind the gear.

Figure #1: Excess Oil in the flywheel bolt holes

SYMPTOM(s)
Oil will leak from the lower flywheel housing area and coat the interior of the flywheel housing in a manner similar to a rear
crankshaft seal leak.

SPECIAL TOOL(s) / SOFTWARE
Tool Description

Tool Number

Comments

M20 Guide Pins (2)

11-729-05-05

Part of 11-729-05 Trans
Service Kit

Rear Crank Seal
Removal Tool
Rear Crank Seal
Installation Tool
Camshaft Locking
Tool

Instructions

12-183-08

Service Manual Link

12-183-09

Service Manual Link

12-357-01

SERVICE PARTS INFORMATION
Kit Description

Part Number

Rear Crank Seal Kit

2523699C91

Quantity
Notes
Required
1

Loctite 574 Flange Sealant

LOC230649KK

1

Gear Assy, Crankshaft

121691N91

1

Rocker Cover Gasket

118225N1

1

One Tube Services
Multiple Gears

REPAIR STEP(s)
.

Please read the entire procedure BEFORE beginning the repair. A maximum
time limit of 2 hours between steps 13 and 16 must be strictly observed for
the repair to be effective.

Figure #2: New 121691N91 Crankshaft Gear ID

IDENTIFYING THE NEW CRANKSHAFT GEAR
The new "laser-structured" crankshaft gear can be identified by dark rings around each of the 10 flywheel bolt holes on the
backside
of the gear (Figure #2). The instructions below must be followed exactly to install the new gear.
INSPECTION / REMOVAL PROCEDURE:
When inspecting for the source of excess oil coating the inside of the engine flywheel housing, please follow the steps
below
once the transmission and clutch have been removed (flywheel on).

1. Disconnect the batteries
2. Set the engine to TDC following instructions in the Service Manual
3. Begin removing the flywheel bolts, inspect each one for the presence of excess oil on the bolt shanks
4. If any of the flywheel bolts are wet with excess oil, proceed through this article
5. If no oil is found on the bolts, DO NOT proceed with this instruction and continue with the diagnosis to locate the source of
the oil (possible crank seal).
6. Remove the valve cover and install the 12-357-01 camshaft locking tool
7. Before removing the crankshaft seal, clean the oil from inside the flywheel and transmission housings using brake cleaner or
a similar degreaser.
This will help to prevent any false indications of an oil leak in the future, and will also keep cleaning debris from entering the
crankcase.
8. Remove the rear crankshaft seal following the instructions linked HERE
9. Thread two of the 11-729-05-05 M20 guide studs through the crank gear and into the crankshaft

10. The crank gear should be able to be worked loose with even side-to-side force and slide off over the two guide studs
11. Clean any oil from the face of the crankshaft after the gear has been removed.

ASSEMBLY PROCEDURE:
12. Clean the mating surface of the new crankshaft gear and the rear face of the crankshaft with Brake Clean or similar
degreaser.

Beginning with step 13 below, there is a MAXIMUM allowable repair time of 2 hours from
application of the sealant to the final torque of the flywheel at step 16. It is strongly
suggested to have all the necessary parts clean and ready to assemble, and all specialty
tools on hand before beginning assembly.

Figure #3: Applying the Loctite 574 Sealant

13. Apply a smooth 1.5mm bead of Loctite 574 at the inner radius of the new gear (Figure #3), holding the tube at a 45° angle;
do not cut the tip of the sealant tube.
See figure #4 below for examples of the correct and incorrect amount of sealant used

Figure #4: Examples of Sealant Quantity and Position
Item 1: OK, sealant bead is evenly applied only in the inner radius of the gear
Item 2: NOT OK, excess sealant applied unevenly. Requires sealant to be removed and reapplied properly

14. Thread the two M20 guide pins into the crankshaft. Carefully position the new gear over the studs so that the alignment pin
(dowel) in the gear aligns with the hole in the rear of the crankshaft. Make sure the gear fully bottoms out against the crankshaft
and that BOTH the lower oil pump drive gear and upper idler gear are properly meshed. A clean plastic or rubber mallet may be
needed to gently tap the gear side to side evenly to get it to fully seat.

Make certain the lower oil pump gear is properly meshed with
the new crankshaft gear. See figure #5, if the oil pump gear is
NOT meshed, it will snap when the flywheel bolts are torqued,
resulting in NO oil pressure on startup.

Figure #5: USE CAUTION that the oil pump to crankshaft gear is fully meshed.

15. Install the new rear crankshaft seal following the instructions in the Service Manual
16. Using the two M20 guide pins again, install the flywheel with new bolts as outlined in the Service Manual and torque to specifications.
17. Remove the 12-357-01 camshaft locking tool and install the valve cover per the Service Manual instructions.
18. Finish with the installation of the clutch and transmission

WARRANTY INFORMATION
Warranty Claim Coding:
Refer to the Warranty Coding Manual for Group and Noun Codes.

Standard Repair Time(s):
Refer to the SRT Manual for Repair Times

OTHER RESOURCES
Master Service Information Site

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