Toyota Diesel 3L 5L 5L-E OEM Rear Main Crankshaft Seal 90311-85008

Product Overview

Genuine OEM Toyota Rear Main Crankshaft Seal 90311-85008, compatible with Toyota Hilux, Hiace, and Dyna models equipped with the 3L, 2.8L, and 5L / 5L-E 3.0L diesel engines. This rear crankshaft oil seal prevents engine oil from escaping past the rear journal, protecting your drivetrain and keeping your diesel leak-free. The L-series diesel engines, particularly the 3L and 5L, are notorious for rear main seal weeping as mileage accumulates and crankcase pressure increases, making this a high-demand replacement item for any Hilux or Hiace diesel service. Genuine Toyota OEM construction ensures the correct lip profile, material durometer, and dimensional precision for a lasting repair on these high-crankcase-pressure diesel applications.

OEM Part Number(s):

• 90311-85008 (primary)
• 90311-85009 (superseded)
• 9008031021 (legacy reference)

 

Key Features & Benefits

• Stops Diesel Rear Main Leaks: Seals the rear crankshaft journal on 3L and 5L diesel engines, eliminating oil loss at the flywheel end that these engines are known for
• OEM-Exact Dimensions: 85x105x10mm lip seal profile engineered to Toyota factory tolerances — no shimming, trimming, or fitment guesswork
• Diesel-Rated Construction: Type T oil seal with precision lip geometry suited to the elevated crankcase pressures typical of the L-series diesel engine family
• Protects Clutch and Bellhousing: A leaking rear main seal on a manual Hilux will contaminate the clutch disc. Catching it early with a genuine OEM seal prevents the much higher cost of a ruined clutch kit
• Cost-Effective Preventive Service: Replace during any clutch, flywheel, or transmission removal. The seal cost is minimal compared to a repeat transaxle or gearbox drop

 

Technical Specifications

Part Type: Engine Rear Main Crankshaft Seal (Seal, Engine Rear Oil / Seal, Type T Oil)
OEM Part Number: 90311-85008
Supersession: 90311-85009
Dimensions: 85mm ID × 105mm OD × 10mm Width
Position: Rear crankshaft (flywheel end)
Material: NBR rubber lip with metal carrier (Type T construction)
Engine Compatibility: 3L 2.8L diesel, 5L / 5L-E 3.0L diesel

Fitment

Year	Model	Engine
1988-1997	Hilux (LN85, LN86, LN106, LN107, LN110, LN111)	3L 2.8L diesel
1998-2005	Hilux (LN147, LN152, LN167, LN172)	5L / 5L-E 3.0L diesel
1989-2005	Hiace (LH Series)	3L 2.8L / 5L 3.0L diesel
1995-2005	Dyna (LY Series)	5L 3.0L diesel

Important: This seal fits the Toyota 3L, 2.8L, and 5L / 5L-E 3.0L diesel engines. It does not fit the 1KZ-TE, 1KD-FTV, or 2KD-FTV engines — those applications use different rear main seals with different dimensions. Always verify your engine code before ordering. The current superseding part number is 90311-85009, which is dimensionally identical and will arrive interchangeably.

Installation & Maintenance

Installation Difficulty: Intermediate–Advanced
Tools Required: Floor jack and stands, transmission jack, complete socket set (metric), torque wrench, seal driver or appropriately sized socket to press seal flush, RTV sealant if rear oil seal housing is disturbed
Professional Installation: Recommended gearbox removal on body-on-frame Hilux and Hiace platforms is manageable for experienced DIYers but requires adequate equipment and time. The seal replacement itself is straightforward once the gearbox is out.

Maintenance Tips:

• Always replace the rear main seal any time the gearbox or transfer case is removed for clutch service. The additional parts cost is negligible against the labor already invested
• Inspect the crankshaft journal sealing surface for wear grooves before fitting the new seal — a grooved journal will cause even a fresh OEM seal to weep immediately; a speedi-sleeve may be required if wear is present
• Lightly coat the seal lip with clean engine oil prior to installation to prevent dry-start damage on first startup
• Press the seal squarely into the housing using a correctly sized driver an off-angle installation will distort the lip and cause immediate leakage on these diesel applications

 

Frequently Asked Questions

Q: What is included in this listing?
A: This listing includes one (1) genuine OEM Toyota rear main crankshaft seal, part number 90311-85008. The seal is supplied as a single component; no gaskets, hardware, or additional seals are included.

Q: Why do the 3L and 5L diesel engines leak at the rear main more than other Toyota engines?
A: The L-series diesels are known for higher crankcase pressure relative to petrol engines of the same era, particularly as piston ring and bore wear accumulate over high mileage. This elevated crankcase pressure accelerates lip seal fatigue at the rear main position. The original rubber compound also ages and hardens over time, reducing lip contact and sealing force. A genuine OEM replacement seal restores full sealing performance, but it is also worth checking the condition of the crankcase breather/PCV system if the new seal leaks soon after installation. Excess blowby pressure will defeat any seal.

Q: Will this seal fit the 1KZ-TE, 1KD-FTV, or 2KD-FTV engines?
A: No. The 90311-85008 is specific to the older L-series diesel engine family (3L, 2.8L, and 5L / 5L-E 3.0L). The 1KZ-TE uses a different rear main seal (90311-95008, 95×115×9.5/12mm), and the 1KD-FTV and 2KD-FTV engines use a different seal again. Mixing up these seals will result in either an oversized or undersized fit and an immediate leak. Verify your engine code.  The LN-prefix chassis codes indicate an L-series diesel, while the KZN-prefix indicates a 1KZ-TE engine.

Q: Do I need to remove the gearbox to replace the rear main seal on a Hilux diesel?
A: Yes. The rear main crankshaft seal on the 3L and 5L Hilux is located between the engine block and the flywheel, which sits behind the clutch assembly and bellhousing. Full gearbox removal is required to access it. On the body-on-frame Hilux, this is a moderate but involved job estimated at 4–10 hours depending on experience and whether a transfer case is also fitted. The seal replacement itself takes under 30 minutes once the gearbox is out, making this the ideal time to also replace the clutch disc, pressure plate, and rear gearbox input shaft seal.

Q: How do I identify a rear main seal leak vs. an oil pan or timing cover leak on my Hilux diesel?
A: A rear main seal leak on the 3L or 5L produces oil accumulation at the very rear of the engine block, specifically pooling in the bellhousing area and coating the flywheel, clutch dust cover, and lower bellhousing. It is distinctly located at the junction between the engine block and gearbox, not at the oil pan seam (which sits lower and further forward), and not at the front of the engine near the crankshaft pulley. If the oil is concentrated in the bellhousing and the flywheel shows oil contamination when the gearbox is dropped, the rear main seal is the source.

Related Toyota Parts You May Need

• Clutch Kit (disc, pressure plate, release bearing), with the gearbox already removed, replace the clutch assembly if wear is evident; combination service is the most cost-effective approach
• Flywheel Resurface or Replacement. Inspect the flywheel friction surface for heat cracking and scoring from clutch wear; resurface or replace as required while access is available
• Gearbox Input Shaft Seal. Replace simultaneously to prevent oil migration into the bellhousing from the gearbox side after the repair
• Crankcase Breather / PCV Valve. Inspect and clean the crankcase ventilation system; a blocked breather elevates crankcase pressure and is a common root cause of repeat rear main seal failure on high-mileage L-series diesels

 

Common Symptoms of a Failing 3L / 5L Diesel Rear Main Seal

• Oil pooling in the bellhousing or on the clutch dust cover, discovered during clutch inspection or gearbox removal
• Unexplained oil drips from between the engine and gearbox on the underside of the vehicle
• Clutch slippage or chatter on engagement, oil contamination of the clutch disc, is a direct consequence of an ongoing rear main leak on manual transmission Hilux models
• Gradual oil level drop with no visible source at the valve cover, oil pan drain plug, or front of the engine
• Oil smell or light smoke from underneath the vehicle at operating temperature, as engine oil contacts the exhaust system after migrating along the underside