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Porsche // 911 & 912 (1965-1989) // 911 1968-1973 2.2L / 2.4L / 2.7L RS LWB (F)
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Crankshaft Main Bearing O-Ring, 51x 4.5. Porsche 911 78-89 / 964 / 993 / 996 Turbo / 997 Turbo / GT3 - 99970728541
99970728541/1
Vehicle Group
- 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 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 TURBO 2007-09
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
- Porsche 997 MKII GT3 / GT3 RS 2010-11
- Porsche 997 MKII Turbo 2010-13
Information
Crankshaft Main Bearing O-Ring, 51x 4.5
This OE Match crankshaft main bearing O-ring is a replacement sealing ring for Porsche 911 1978–1989, 964, 993, 996 Turbo, 997 Turbo, and GT3 models. Measuring 51 x 4.5, it is designed to match the original-style fitment and sealing function within the crankshaft / main bearing area.
Sold individually
Fits:
Porsche 911 1978 - 1989
Porsche 964 1989 - 1994
Porsche 993 1995 - 1998
Porsche 996 Turbo 3.6L 2001 - 2005
Porsche 996 GT3 3.6L 1999 - 2005
Porsche 997.1 Turbo 3.6L 2007 - 2009
Porsche 997.2 Turbo 3.6L 2010 - 2013
Porsche 997 GT3 3.6L / 3.8L / 4.0L 2007 - 2011
Diagram ref no 21
The crankshaft main bearing O-ring helps seal the relevant bearing or housing connection to prevent oil leakage and maintain correct engine oil sealing. A properly sealing O-ring is essential for protecting engine components and maintaining oil system integrity.
What This Part Does / Functions
• Replaces the crankshaft main bearing
• O-ring Helps seal the crankshaft / main bearing housing area
• Supports correct engine oil sealing
• Helps prevent oil leaks from aged or flattened seals
• Suitable for engine rebuild, crankshaft, or bearing service
• Replaces hardened, cracked, flattened, swollen, or damaged O-rings
• OE Match replacement for Porsche engine sealing repair.
Why Replace This Part?
O-rings can harden, flatten, crack, swell, or lose sealing ability due to heat, age, oil exposure, pressure, and engine service work. A worn or damaged crankshaft main bearing O-ring may allow oil seepage or leakage, affecting engine cleanliness and oil system reliability. Replacement is recommended whenever the related engine components are removed or when oil leakage is present.
When to Replace This Part
• Engine rebuild or major engine service is being carried out
• Crankshaft or main bearing components are being serviced
• Oil leakage is present around the related sealing area
• The original O-ring is hardened, flattened, cracked, or damaged
• Bearing housing or crankshaft sealing components have been removed
• Preventative replacement is required during engine assembly
• The vehicle is undergoing Porsche engine restoration
Where it fits on the car
This O-ring fits within the engine crankshaft / main bearing sealing area. Exact position can vary depending on engine type and model-specific crankcase layout.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970728541
The product you are viewing cross references to these numbers
This OE Match crankshaft main bearing O-ring is a replacement sealing ring for Porsche 911 1978–1989, 964, 993, 996 Turbo, 997 Turbo, and GT3 models. Measuring 51 x 4.5, it is designed to match the original-style fitment and sealing function within the crankshaft / main bearing area.
Sold individually
Fits:
Porsche 911 1978 - 1989
Porsche 964 1989 - 1994
Porsche 993 1995 - 1998
Porsche 996 Turbo 3.6L 2001 - 2005
Porsche 996 GT3 3.6L 1999 - 2005
Porsche 997.1 Turbo 3.6L 2007 - 2009
Porsche 997.2 Turbo 3.6L 2010 - 2013
Porsche 997 GT3 3.6L / 3.8L / 4.0L 2007 - 2011
Diagram ref no 21
The crankshaft main bearing O-ring helps seal the relevant bearing or housing connection to prevent oil leakage and maintain correct engine oil sealing. A properly sealing O-ring is essential for protecting engine components and maintaining oil system integrity.
What This Part Does / Functions
• Replaces the crankshaft main bearing
• O-ring Helps seal the crankshaft / main bearing housing area
• Supports correct engine oil sealing
• Helps prevent oil leaks from aged or flattened seals
• Suitable for engine rebuild, crankshaft, or bearing service
• Replaces hardened, cracked, flattened, swollen, or damaged O-rings
• OE Match replacement for Porsche engine sealing repair.
Why Replace This Part?
O-rings can harden, flatten, crack, swell, or lose sealing ability due to heat, age, oil exposure, pressure, and engine service work. A worn or damaged crankshaft main bearing O-ring may allow oil seepage or leakage, affecting engine cleanliness and oil system reliability. Replacement is recommended whenever the related engine components are removed or when oil leakage is present.
When to Replace This Part
• Engine rebuild or major engine service is being carried out
• Crankshaft or main bearing components are being serviced
• Oil leakage is present around the related sealing area
• The original O-ring is hardened, flattened, cracked, or damaged
• Bearing housing or crankshaft sealing components have been removed
• Preventative replacement is required during engine assembly
• The vehicle is undergoing Porsche engine restoration
Where it fits on the car
This O-ring fits within the engine crankshaft / main bearing sealing area. Exact position can vary depending on engine type and model-specific crankcase layout.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99970728541
99970146740
99970728540
99970728541
The product you are viewing cross references to these numbers
Price: £5.50
In stock
Related products
Vehicle Group
- 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 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 914 (1970-1976)
Information
Crankshaft / V-Belt Pulley Hex Head Bolt. M12 x 1.5 x 22.
Fits:
Porsche 911 1965-89
Porsche 914 1970-76
Porsche 964 Turbo 3.3L 1991-92
Click 'Zoom in' for large parts diagram
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99909300502
The product you are viewing cross references to these numbers
Fits:
Porsche 911 1965-89
Porsche 914 1970-76
Porsche 964 Turbo 3.3L 1991-92
Click 'Zoom in' for large parts diagram
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99909300502
99909300502
The product you are viewing cross references to these numbers
Price: £10.56
In stock
Vehicle Group
- 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 914 (1970-1976)
Information
Crankshaft v-belt pully 116.5mm.
Fits:
Porsche 911 08/1968-75 (not Sportomatic)
Porsche 914 1970-76
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110201750
The product you are viewing cross references to these numbers
Fits:
Porsche 911 08/1968-75 (not Sportomatic)
Porsche 914 1970-76
Diagram ref no 15
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
91110201750
91110201750
The product you are viewing cross references to these numbers
£139.00
Now £125.10
In stock
Vehicle Group
- 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 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- 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 997 MK1 TURBO 2007-09
- Porsche 997 MKII Turbo 2010-13
- Porsche 356 1950-55
- Porsche 356A 1955-59
- Porsche 356B 1959-63
- Porsche 356C 1963-65
- Porsche 914 (1970-1976)
Information
Lock snap ring for brass gear. Number 0
Size: 2.4mm
Fits:
Porsche 356
Porsche 911
Porsche 912
Porsche 964
Porsche 993
Porsche 914
Porsche 996 Turbo / GT3
Porsche 997 Turbo / GT3
Click 'Zoom in' for large parts diagram.
Diagram ref no 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110214800
The product you are viewing cross references to these numbers
Size: 2.4mm
Fits:
Porsche 356
Porsche 911
Porsche 912
Porsche 964
Porsche 993
Porsche 914
Porsche 996 Turbo / GT3
Porsche 997 Turbo / GT3
Click 'Zoom in' for large parts diagram.
Diagram ref no 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110214800
90110214800
The product you are viewing cross references to these numbers
Price: £7.55
In stock
Vehicle Group
- 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 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 914 (1970-1976)
Information
Crankshaft timing gear.
*** to be used for code no: 0
Fits:
Porsche 911 1965-89
Porsche 914-6 1970-76
Porsche 964 Turbo 3.3L 1991-92
Click 'Zoom in' for large parts diagram.
Diagram ref no 11
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90110211102
The product you are viewing cross references to these numbers
*** to be used for code no: 0
Fits:
Porsche 911 1965-89
Porsche 914-6 1970-76
Porsche 964 Turbo 3.3L 1991-92
Click 'Zoom in' for large parts diagram.
Diagram ref no 11
Related reference numbers
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90110211102
90110211102
90110211100
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Price: £436.38
Orderable