Rear main oil seal - crank rear. Porsche 911 78-89 / 930  ❭  99911342641

Rear main oil seal - crank rear.
Fitting Position: Transmission End
Inner Diameter: 90 mm, Outer diameter: 110 mm, Width: 12 mm
Radial Shaft Seal Design.

Fits:
Porsche 911 3.0L 1978 - 1983
Porsche 911 3.2L 1984 - 1989
Porsche 930 Turbo 1975 - 1989

Diagram Ref No 33

The rear main oil seal fits at the rear of the crankshaft where it passes through the engine case. It helps retain engine oil inside the crankcase and prevents oil from leaking into the flywheel, clutch, or transmission bellhousing area.

Functions
•  Replaces the rear crankshaft oil seal
•  Helps seal the rear of the engine crankshaft
•  Helps prevent engine oil leaks from the bellhousing area
•  Protects the clutch and flywheel area from oil contamination
•  Supports correct crankcase oil retention
•  Replaces hardened, worn, split, leaking, or damaged original seals
•  OE Match replacement for Porsche 911 and 930 engine service.

Why Replace This Part?
Rear main oil seals are exposed to heat, crankshaft rotation, oil, pressure changes, and age-related wear. Over time, the seal can harden, shrink, crack, wear, or lose sealing ability. A failed rear main seal may cause oil leaks between the engine and gearbox, oil contamination on the clutch, burning oil smells, or visible oil dripping from the bellhousing area. Replacing the seal helps restore a clean, reliable crankshaft seal.

When to Replace This Part
•   Oil is leaking from between the engine and gearbox
•   Oil drips are visible from the bellhousing area
•   The clutch or flywheel is contaminated with oil
•   The engine or gearbox has been removed
•   The flywheel is being removed or replaced
•   The original seal is hardened, worn, split, or leaking
•   Preventative replacement is being carried out during clutch or engine service.

Where it fits on the car
This oil seal fits at the rear crankshaft position on Porsche 911 and 930 engines. It sits between the crankshaft and engine case, behind the flywheel area.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99911342641

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