Flywheel / Torque

• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93
• Porsche 993 (911) RS 1994-97
• Porsche 996 GT3 MKI 1999-02
• Porsche 997 MK1 GT3 / GT3 RS 2007-09  

• Transfers engine torque to the clutch and transmission.
• Provides the friction surface for clutch engagement.
• Stores and transfers rotational energy from the crankshaft.
• Reduces rotational mass compared to heavier flywheel designs.
• Improves throttle response and engine acceleration.
• Allows the engine to gain and shed revs more quickly.
• Enhances driver engagement and performance characteristics.
• Supports smooth and reliable clutch operation.

• Clutch judder or vibration during engagement.
• Excessive drivetrain vibration.
• Difficulty achieving smooth gear changes.
• Uneven clutch engagement or clutch chatter.
• Hot spots, scoring or cracking on the flywheel surface.
• Premature clutch wear.
• Burning clutch odours during operation.
• Rattling or knocking noises from the bellhousing area.
• Reduced throttle response and drivetrain smoothness.
• Excessive wear on associated clutch components.

• The flywheel is subjected to continuous engine torque, clutch friction, heat cycles and mechanical stress throughout its service life. Over time, the clutch contact surface can become worn, warped or heat-damaged, reducing clutch efficiency and negatively affecting vehicle drivability.
• A worn flywheel can cause clutch vibration, poor engagement characteristics and accelerated wear of the clutch disc and pressure plate. Continuing to use a damaged flywheel may compromise the performance of newly installed clutch components and increase the likelihood of more extensive drivetrain repairs.
• Replacing a worn flywheel with an OE Match Single Mass RS Flywheel restores reliable clutch operation while delivering enhanced engine responsiveness and a more engaging driving experience. Precision-balanced and manufactured from durable materials, it offers factory-style fitment, long-term reliability and performance characteristics sought after by Porsche enthusiasts and performance-focused drivers.

Rear Main Oil Seal for Porsche 

Restore engine sealing integrity and prevent costly oil leaks with this OE Match Rear Main Oil Seal for the Porsche 964, Porsche 993 and Porsche 996. Manufactured to OE specifications and measuring 90mm inner diameter, 110mm outer diameter and 12mm width, this critical engine seal is designed to prevent engine oil escaping around the rear of the crankshaft where it exits the engine case and connects to the flywheel assembly.

Fits:

• Porsche 964 (911) C2 1989-93
• Porsche 964 (911) C4 1989-93
• Porsche 964 (911) RS 3.6L 1991-93
• Porsche 964 (911) RS 3.8L 1991-93
• Porsche 964 (911) TURBO 3.3L 1991-93
• Porsche 964 (911) TURBO 3.6L 1991-93
• Porsche 993 (911) C2 1994-97
• Porsche 993 (911) C4 1994-97
• Porsche 993 (911) RS 1994-97
• Porsche 993 (911) C2S 1994-97
• Porsche 993 (911) C4S 1994-97
• Porsche 993 (911) TURBO 1994-96
• Porsche 993 (911) GT2 1994-97
• Porsche 993 (911) TURBO S 1994-97
• Porsche 996 TURBO 2000-05
• Porsche 996 GT2 2001-05
• Porsche 996 GT3 MKI 1999-02
• Porsche 924S 2.5L 1986-87
• Porsche 924S 2.5L 1988
• Porsche 944 2.5L 8V 1982-87
• Porsche 944 2.7L 8V 1988-89
• Porsche 944S 2.5L 16V 1987-88
• Porsche 944S2 3.0L 16V 1989-91
• Porsche 944 Turbo 2.5L 8V 1985-88
• Porsche 944 Turbo 2.5L 8V 1989-91
• Porsche 944 Turbo S 2.5L 8V 1988
• Porsche 968 3.0L 1992-94
• Porsche 968 Sport 3.0L 1994-95
• Porsche 968 CS 3.0L 1993-95
• Porsche 968 Turbo S 3.0L 1993-94
• Porsche 928 4.5L 1978-82
• Porsche 928S 4.7L 1981-83
• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

The rear main oil seal, often referred to as the RMS (Rear Main Seal), is one of the most important sealing components in the engine. It retains engine oil inside the crankcase while allowing the crankshaft to rotate at high speed. A worn or damaged seal can lead to oil leaks, clutch contamination and unnecessary engine maintenance costs if left unattended.

This OE Match replacement provides the correct fit, sealing performance and durability required for maintenance, engine rebuilds and preventative servicing.

What Does the Rear Main Oil Seal Do?

The rear main oil seal forms a seal around the rear section of the crankshaft.

Its primary functions include:

• Preventing engine oil leaks
• Sealing the rear crankshaft opening
• Protecting the flywheel area from contamination
• Maintaining correct engine oil levels
• Preventing oil reaching the clutch assembly
• Supporting long-term engine reliability
• Allowing smooth crankshaft rotation

Without a properly functioning rear main seal, oil can escape from the engine and create a range of reliability issues.

Why Do Rear Main Oil Seals Fail?

Like all rubber sealing components, rear main oil seals are subject to wear and ageing.

Common causes of failure include:

• Heat cycling
• Age-related hardening
• Crankshaft wear
• Engine vibration
• Long-term oil exposure
• Improper installation
• Excessive crankcase pressure
• High mileage use

Over time, the sealing lip can lose flexibility and its ability to maintain consistent contact with the crankshaft surface.

Symptoms of a Failing Rear Main Oil Seal

Common warning signs include:

• Oil leaks between engine and gearbox
• Oil drips beneath the vehicle
• Oil contamination around the flywheel housing
• Clutch slip caused by oil contamination
• Burning oil smell
• Gradual oil level loss
• Oil residue on transmission bellhousing

Because the seal is located behind the flywheel, leaks can often be mistaken for other engine oil leaks unless properly diagnosed.

When Should the Rear Main Oil Seal Be Replaced?

Replacement is recommended when:

• Oil leakage is present
• The gearbox is being removed
• Replacing the clutch assembly
• Rebuilding the engine
• Refurbishing the crankshaft
• Carrying out preventative maintenance
• The original seal shows signs of ageing
• Engine mileage is high

Many Porsche specialists recommend replacing the rear main seal whenever the clutch or flywheel is removed, as labour access is significantly easier during these procedures.

Why Replacement Matters

A leaking rear main oil seal can lead to far more expensive repairs if ignored.

Benefits of replacement include:

• Prevention of engine oil leaks
• Protection of the clutch assembly
• Improved engine cleanliness
• Reduced maintenance costs
• Improved reliability
• Professional rebuild standards
• Long-term sealing performance
• Greater peace of mind

Replacing the seal during clutch or engine work is considered a smart preventative maintenance measure.