Flywheel O-Ring Seal - Type 4 Engines, Waterboxer Engines

This flywheel O-ring seal is fitted to Volkswagen Type 4 air-cooled engines in 1700cc, 1800cc, and 2000cc form, as used in Baywindow Buses from 1973 onwards. It is also used on Type 25 (T3) Waterboxer engines in 1900cc and 2100cc capacities. The O-ring sits in the groove at the rear of the crankshaft and seals between the crankshaft and the flywheel.

The flywheel O-ring plays a crucial role in preventing engine oil from leaking past the crankshaft flange and into the clutch and bellhousing area. A hardened, flattened, or damaged O-ring can lead to oil contamination of the clutch, clutch slip, and oil leaks that are often mistaken for a failed rear main seal. For this reason, the O-ring should always be replaced whenever the flywheel is removed.

Manufactured to the correct size and oil-resistant specification, this O-ring provides a reliable seal under normal operating temperatures and engine loads. It is an essential service item during engine rebuilds, clutch replacements, or rear crankshaft seal renewal.

Quantity Required:

• 1 per engine

• Sold individually

Vehicle & Engine Fitment

• T2 Baywindow Bus – Type 4 1700cc, 1800cc, 2000cc (1972–1979, fitted from 1973)

• T25 / T3 Bus – Waterboxer 1.9 & 2.1 engines (1980–1992)

• Porsche 914 – Type 4 engines (1970–1976)

Key Features

• Seals flywheel to crankshaft flange

• Prevents oil leaks into the clutch housing

• Suitable for Type 4 and Waterboxer engines

• Oil-resistant rubber construction

• Essential replacement during flywheel removal

Recommended Associated Parts

• Rear crankshaft oil seal

• Flywheel bolts and washer

• Clutch kit

• Engine gasket set