Genuine Nissan RB Rear Main Crankshaft Oil Seal – RB20 RB25 RB26 RB30 – 12279-5L310
Keep your Nissan RB engine protected against oil leaks with a Genuine Nissan OEM Rear Crankshaft Oil Seal, also commonly known as the rear main seal, designed for compatible Nissan RB-series engines including the legendary RB26DETT.
Located at the rear of the engine where the crankshaft exits the engine block towards the flywheel or flexplate, the rear main seal helps prevent engine oil from escaping into the bellhousing area.
Over time, original crankshaft seals can harden, deteriorate or wear due to age, heat exposure and engine operation. A worn rear main seal may result in oil leaks between the engine and gearbox, potentially contaminating nearby drivetrain components.
As accessing the rear crankshaft oil seal generally requires removal of the gearbox and associated drivetrain components, replacing the seal during a clutch replacement, flywheel upgrade or engine rebuild is a sensible preventative maintenance measure.
Whether you're rebuilding an RB26DETT, replacing the clutch on your RB25DET Skyline or refreshing an RB30-powered vehicle, a genuine Nissan rear main seal provides factory-style fitment and dependable sealing performance.
Product Details
- Brand: Genuine Nissan
- Part Number: 12279-5L310
- Product Type: Rear Crankshaft Oil Seal / Rear Main Seal
- Installation Position: Rear of Engine – Crankshaft / Flywheel End
- Application: Compatible Nissan RB-Series Engines
- Material: OEM Oil-Resistant Sealing Material
- Quantity: 1 Oil Seal
- Condition: Brand New – Genuine Nissan OEM
Engine Compatibility
- Nissan RB20DE – Compatible applications
- Nissan RB20DET – Compatible applications
- Nissan RB25DE – Compatible applications
- Nissan RB25DET – Compatible applications
- Nissan RB26DETT – Compatible applications
- Nissan RB30E – Compatible applications
- Nissan RB30ET – Compatible applications
Important: Rear crankshaft oil seal compatibility can vary depending on engine production date, engine configuration and previous modifications. Please confirm Nissan part number 12279-5L310 against your engine before purchasing.
Vehicle Compatibility
- Nissan Skyline R31 – Selected RB-powered models
- Nissan Skyline R32 – Selected RB-powered models
- Nissan Skyline R33 – Selected RB-powered models
- Nissan Skyline R34 – Selected RB-powered models
- Nissan Skyline R32 GT-R (BNR32) – RB26DETT
- Nissan Skyline R33 GT-R (BCNR33) – RB26DETT
- Nissan Skyline R34 GT-R (BNR34) – RB26DETT
- Nissan Stagea WC34 – Selected RB-powered models
- Nissan Laurel C33 / C34 – Selected RB-powered models
- Nissan Cefiro A31 – Selected RB-powered models
- Holden VL Commodore – Selected RB30-powered models, subject to part number confirmation
Please verify compatibility using your vehicle's VIN, engine details or original Nissan part number before ordering, particularly for engine-swapped or modified vehicles.
Key Features & Benefits
- Genuine Nissan OEM replacement crankshaft oil seal
- Designed for compatible RB20, RB25, RB26 and RB30 engines
- Helps prevent engine oil leaks from the rear crankshaft area
- Manufactured to Nissan original equipment specifications
- Provides factory-style fitment and sealing performance
- Ideal for clutch replacements and flywheel upgrades
- Recommended as preventative maintenance during engine or gearbox work
- Suitable for standard and modified RB engine builds
- Helps protect the bellhousing area from engine oil contamination
Why Replace Your Rear Main Seal?
The rear crankshaft oil seal is an important engine sealing component that prevents oil from escaping where the crankshaft passes through the rear of the engine.
After years of heat exposure and engine operation, the original seal may lose flexibility or develop wear around its sealing lip, increasing the risk of oil leakage.
Common signs of a deteriorated rear main seal may include:
- Engine oil leaking from the engine-to-gearbox area
- Oil residue around the lower bellhousing
- Oil contamination near the flywheel or clutch assembly
- Visible damage, hardening or wear when the original seal is removed
Oil leaks in this area can also originate from other engine or gearbox components, so the source should be confirmed before replacing the seal.
Recommended During Clutch & Flywheel Replacement
Replacing the rear main seal while the gearbox and flywheel are already removed can help avoid the additional labour involved in accessing the seal at a later date.
This makes the genuine Nissan rear crankshaft oil seal an excellent addition to:
- Clutch replacement jobs
- Flywheel replacements or upgrades
- Manual gearbox conversions
- RB engine rebuilds
- Engine and gearbox removal or installation
- Preventative maintenance on high-kilometre engines
Important Installation Information
Correct installation is essential to ensure effective sealing and avoid premature oil leakage.
Before fitting the new seal, inspect the crankshaft sealing surface and surrounding housing for damage, wear or contamination.
Use the appropriate installation tools and follow the Nissan factory workshop procedures for seal positioning, lubrication and installation depth.
Avoid damaging the sealing lip or installing the seal unevenly, as incorrect installation may result in oil leakage.
Professional installation is recommended.
Why Choose Genuine Nissan?
Genuine Nissan replacement oil seals are manufactured to original equipment specifications, providing the correct factory-style fitment, sealing characteristics and quality expected from OEM engine components.
For RB-series engines, particularly valuable Skyline GT-R and performance builds, using genuine Nissan sealing components is an excellent way to maintain engine reliability and originality.
Note: This listing includes one (1) Genuine Nissan Rear Crankshaft Oil Seal – 12279-5L310 only. Additional gaskets, sealants, installation tools and other components are not included. Supplied in genuine Nissan OEM packaging, which may be removed for product photography.
Australian Stock & Fast Dispatch: At OEM4JDM, every part listed as In Stock is physically on our shelf in Australia and ready for fast dispatch.