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Crankcase Parts
By OE Match
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
Length: 21.5mm, Diameter: 6.2mm
Fits:
Porsche 928 S4 - 1987 to 1992
Porsche 928 GT - 1989 to 1991
Diagram ref no 17
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110101101
The product you are viewing cross references to these numbers
This kit is comprised of the following items:
- 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
Front crankshaft seal also known as a shaft sealing ring. It sits at the front of the engine, sealing the point where the crankshaft passes through the engine block - typically behind the vibration damper or timing gear. Its purpose is to keep engine oil contained while allowing the crankshaft to spin freely.
Fits:
Porsche 928 1978 - 1995
Diagram ref no 3
Over time, the crankshaft seal can wear down from constant heat, oil exposure, and friction. The rubber lip may harden, crack, or become damaged, losing its ability to seal properly. When this happens, oil begins to leak, which can create a mess, damage engine components, or cause belts and pulleys to slip if oil spreads across them.
How to Know If It’s Failing:
You might suspect the seal is failing if you notice:
• Oil dripping or forming a puddle under the front section of the engine.
• Visible oil seepage around the crankshaft front seal area.
• Smoke or burning smell under the hood (oil hitting a hot surface). Low oil levels without visible external damage.
• After so many miles or long periods without seal maintenance, even if there’s not a massive leak yet.
If a worn front crankshaft seal isn’t replaced, the oil leak will usually worsen over time. This can lead to significant oil loss and starve the engine of proper lubrication, causing serious internal damage. Leaking oil may also spread onto belts and pulleys, leading to slippage, premature wear, or even belt failure. In addition to making a mess and degrading nearby components, oil on hot surfaces can pose a fire hazard. Left unchecked, the problem often becomes more expensive to fix, especially if the leak reaches sensors, wiring, or other critical parts.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911326340
The product you are viewing cross references to these numbers
- Porsche 911 1965-1968 2.0L / 912 SWB (F)
- Porsche 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 928 4.5L 1978-82
Fits:
Porsche 911 1965-83
Porsche 928 1978 Only
Diagram ref no 41
A magnetic sump oil drain plug is a type of oil drain plug that contains a small magnet designed to attract and capture metallic particles that may be present in your engine's oil. While this type of drain plug is not exclusive to Porsche and can be used in various vehicles, it can provide several benefits, including:
Improved Engine Longevity: The magnet in the drain plug helps to capture tiny metal particles, such as iron, steel, or aluminum, that may circulate in the engine oil. Removing these particles can reduce wear and tear on engine components, potentially extending the engine's lifespan.
Enhanced Engine Performance: By reducing the presence of contaminants in the oil, a magnetic drain plug can help maintain the oil's lubricating properties, which is crucial for smooth engine operation. Clean oil can also contribute to improved fuel efficiency.
Early Detection of Problems: As the magnetic drain plug collects metallic debris, it can serve as an early warning system. By inspecting the drain plug during oil changes, you can get an idea of the engine's condition and detect any unusual wear or damage before it becomes a major issue.
Reduced Maintenance Costs: Regularly inspecting and cleaning a magnetic drain plug can prevent larger issues from developing over time. Addressing potential problems early can save you money on more extensive repairs down the road.
Peace of Mind: Knowing that you are taking steps to protect your engine from premature wear and tear can give you peace of mind as a vehicle owner. It's a relatively inexpensive and simple modification that can provide added assurance.
Easy Installation: Magnetic drain plugs are typically straightforward to install. They often replace the existing drain plug and require no special tools or modifications.
While magnetic drain plugs can offer these benefits, it's essential to remember that they are not a substitute for regular oil changes and proper maintenance. Regular oil changes with the appropriate oil and filter are still crucial for the health and longevity of your engine. Additionally, magnetic drain plugs may not capture all types of contaminants, so they should be seen as a supplementary measure rather than a comprehensive solution.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110717603
The product you are viewing cross references to these numbers
- Porsche 911 1974-1977 2.7L / 1976-77 3.0 Carrera
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1978-1989 3.3L Turbo (930)
- 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 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- 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
Fits:
Porsche 911 3.2 Carrera - 1984 to 1989 Oil Drain Plug for side of crankcase
Porsche 911 - 1978 to 1984 Oil Drain plug for sump plate
Porsche 964 - 1989 to 1994
Porsche 993 - 1995 to 1998
Porsche 996 turbo / GT3 -
Porsche 924S - 1986 to 1988
Porsche 944 - 1982 to 1991
Porsche 968 - 1992 to 1995
Porsche 928 - 1978 to 1995
Diagram ref no 22
A magnetic sump oil drain plug is a type of oil drain plug that contains a small magnet designed to attract and capture metallic particles that may be present in your engine's oil. While this type of drain plug is not exclusive to Porsche and can be used in various vehicles, it can provide several benefits, including:
Improved Engine Longevity: The magnet in the drain plug helps to capture tiny metal particles, such as iron, steel, or aluminum, that may circulate in the engine oil. Removing these particles can reduce wear and tear on engine components, potentially extending the engine's lifespan.
Enhanced Engine Performance: By reducing the presence of contaminants in the oil, a magnetic drain plug can help maintain the oil's lubricating properties, which is crucial for smooth engine operation. Clean oil can also contribute to improved fuel efficiency.
Early Detection of Problems: As the magnetic drain plug collects metallic debris, it can serve as an early warning system. By inspecting the drain plug during oil changes, you can get an idea of the engine's condition and detect any unusual wear or damage before it becomes a major issue.
Reduced Maintenance Costs: Regularly inspecting and cleaning a magnetic drain plug can prevent larger issues from developing over time. Addressing potential problems early can save you money on more extensive repairs down the road.
Peace of Mind: Knowing that you are taking steps to protect your engine from premature wear and tear can give you peace of mind as a vehicle owner. It's a relatively inexpensive and simple modification that can provide added assurance.
Easy Installation: Magnetic drain plugs are typically straightforward to install. They often replace the existing drain plug and require no special tools or modifications.
While magnetic drain plugs can offer these benefits, it's essential to remember that they are not a substitute for regular oil changes and proper maintenance. Regular oil changes with the appropriate oil and filter are still crucial for the health and longevity of your engine. Additionally, magnetic drain plugs may not capture all types of contaminants, so they should be seen as a supplementary measure rather than a comprehensive solution.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
94410719711
The product you are viewing cross references to these numbers
- Porsche 911 1978-1983 3.0L / SC
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 928S4 5.0L 1987-92
- Porsche 928GT 5.0L 1989-91
Length: 21.5mm, Diameter: 6.2mm
Fits:
Porsche 911 SC - 1978 to 1983 (6 required)
Porsche 911 3.2 Carrera - 1984 to 1989 (6 required)
Porsche 928 S4 / 928 GT - 1987 to 1992 (8 required)
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110101101
The product you are viewing cross references to these numbers
- 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
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
Diagram Ref No. 21
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.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99911342642
The product you are viewing cross references to these numbers
OEMatch Crankcase Parts — Durability, Sealing, Performance
OEMatch supplies crankcase parts for Porsche models, including bearing shells, seals, breather valves, dowels, plugs and fasteners for engine rebuilds and scheduled maintenance. These parts restore oil control, bearing alignment and structural rigidity inside the engine and help preserve long-term performance. OEMatch focuses on crankcase parts selected for Porsche applications.
Available Types
- Bearing shells
- Crankcase seals and gaskets
- Breather valves and vents
- Dowels, locating pins and plugs
- Crankcase fasteners and bolts
Understanding OEMatch Crankcase Parts
OEM (Original Equipment Manufacturer) parts are made by the same company that produced your Porsche’s original crankcase parts.
OE (Original Equipment) refers to parts matching original specifications for the crankcase parts and may be supplied by alternative manufacturers. Aftermarket parts offer alternative options, sometimes with enhanced features or better value. OEMatch supplies non-OEM crankcase parts engineered as direct-fit alternatives to OEM parts, made to original-spec dimensions and tolerances for Porsche models.
The crankcase forms the structural core of the engine, housing the crankshaft, main and connecting-rod bearings, and associated oil galleries. It contains and routes oil, maintains alignment for rotating assemblies and controls ventilation to limit pressure build-up and contamination. Correct sealing, dowel alignment and secure fastenings are essential to preserve bearing clearances, minimise oil leakage and prevent premature wear.
Benefits Include
- Restores accurate bearing alignment for smooth crankshaft rotation
- Improves oil sealing to reduce leaks and maintain oil pressure
- Enhances ventilation and contamination control to protect bearings
- Reduces vibration by preserving structural rigidity
Why Crankcase Parts Wear and Fail
- Thermal cycling and mechanical vibration leading to material fatigue
- Oil contamination and breakdown accelerating bearing and seal wear
- Warped or corroded mating faces causing leaks and misalignment
- Fastener fatigue or improper torque resulting in loosening and movement
The Importance of Replacing with OEMatch Crankcase Parts
Replacing worn crankcase parts during an engine rebuild or maintenance service restores correct alignment, sealing and oil control that Porsche engines require. Careful attention to dowels, seals and fasteners helps preserve bearing life and prevents secondary damage. Using parts produced to original-spec dimensions helps maintain clearances and reduces the risk of leaks or accelerated wear across classic and modern Porsche engines.
Advantages
- Manufactured to original-spec dimensions and tolerances for Porsche models
- Designed to work with factory systems and sensors where applicable
- Coverage for both air-cooled and water-cooled Porsche engine architectures