Enter your VAT number here and click Verify:
Your details have been verified. VAT number registered to:
,
.
Your order will now be zero rated for VAT purposes. We reserve the right to verify these details after your order request has been made and reinstate VAT if required.
Your VAT details were not recognised or were invalid. Your VAT number must be matched to your Billing Country as specified above. This is currently specified as . You do not need to enter the country code part of your VAT number as this has already been selected in your billing address details above.
The VAT number checking service is currently offline. Please supply your VAT details within the comments or special instructions field below and we will apply a VAT discount after placing your order request.
Crankshaft & Parts
By OE Match
- 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
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
OEMatch Crankshaft & Parts — Fit, Function, Confidence
OEMatch supplies crankshaft and related engine parts for Porsche models, selected for rebuilds, restorations and major servicing. The range is described to help you identify bearings, seals, fastenings and assembled crankshafts needed to complete an overhaul while preserving engine balance and lubrication integrity.
Available Types
- Complete crankshafts
- Main and rod bearings
- Thrust washers and spacers
- Oil seals and gaskets
- Dowel pins, bolts and pulleys
Understanding OEMatch Crankshaft & Parts
OEM (Original Equipment Manufacturer) parts are made by the same company that produced your Porsche’s original crankshafts and parts.
OE (Original Equipment) refers to parts matching original specifications for the crankshafts and parts and may be supplied by alternative manufacturers. Aftermarket parts offer alternative options, sometimes with enhanced features or better value. OEMatch supplies non-OEM crankshafts and parts engineered as direct-fit alternatives to OEM parts, made to original-spec dimensions and tolerances for Porsche models.
OEMatch provides a wide range of crankshafts and related engine hardware for Porsche applications, supporting repairs across multiple model generations. The crankshaft converts linear piston motion into rotational energy and relies on bearings, seals and correct fastenings to maintain alignment, oil flow and rotational balance.
Benefits Include
- Restores rotational balance and smooth power delivery
- Protects bearings and journals by restoring correct clearances
- Improves oil control and sealing to reduce contamination and wear
Why Crankshaft & Parts Wear and Fail
- Oil starvation or contamination leading to bearing wear and journal scoring
- Imbalance or damaged dampers causing vibration and accelerated fatigue
- Cracks or fatigue from high loads, detonation or extended high-RPM use
- Incorrect assembly torque or alignment during rebuilds
The Importance of Replacing with OEMatch Crankshaft & Parts
Replacing worn crankshaft elements with correctly specified parts restores bearing clearances, oil control and rotational balance that are essential to long-term engine function in Porsche models. Choosing parts described for crankshaft assemblies helps reduce the risk of secondary damage, supports reliable lubrication and aids a smoother, more consistent running engine after rebuild or repair.
Advantages
- Direct-fit alternatives engineered to match original dimensions and tolerances where applicable
- Coverage aimed at classic and modern Porsche engines to support rebuilds and preventive maintenance
- Parts described for clear identification during overhaul and reassembly