Flywheel O-Ring, for Type 4 1700-2000cc

OVERVIEW

When it comes to maintaining the integrity of your high-performance Type 4 air-cooled engine, even the smallest components play a pivotal role in preventing catastrophic oil leaks and keeping your drivetrain clean. This Flywheel O-Ring is specifically engineered for the Volkswagen Type 4 power plant, which is famously found in late-model Transporters, 411 and 412 variants, and the iconic Porsche 914. Located deep within the flywheel assembly, this rubber seal provides the critical barrier between the crankshaft and the flywheel mounting surface. Over years of intense heat cycles and constant exposure to engine oil, the original rubber can become brittle, flattened, or cracked, leading to persistent leaks that can contaminate your clutch disc and cause premature slippage. By replacing this O-ring during any major engine or transmission service, you ensure that your oil stays where it belongsinside the crankcaseprotecting your investment and maintaining the mechanical reliability that air-cooled enthusiasts demand.

At Appletree Automotive, we understand that a "simple" oil leak is never truly simple when it involves the labor of pulling the engine or transaxle. That is why we recommend this EMPI Flywheel O-Ring as a mandatory replacement item whenever the flywheel is removed for a rear main seal change or a clutch replacement. This O-ring is manufactured from high-grade, oil-resistant rubber designed to withstand the intense thermal environments typical of the Type 4 engine bay. Whether you are daily driving a 1975 Westfalia or building a high-torque 2000cc engine for a custom sand rail or street rod, using fresh, high-quality seals is the only way to guarantee a leak-free build. This part is a direct replacement for OEM part number 021-105-279, ensuring a perfect fit and factory-spec compression for a long-lasting seal that won''t let you down when the miles start adding up.

FITMENT

• VW Bus (Type 2): 1972-1979 (1700cc, 1800cc, and 2000cc engines)
• VW 411 / 412: All models equipped with Type 4 engines
• Porsche 914: 1970-1976 (1.7L, 1.8L, and 2.0L 4-cylinder models)
• Custom Applications: Any sand rail, buggy, or trike utilizing a Type 4 engine case

SPECS

• Application: Volkswagen Type 4 / Porsche 914 Engines
• Engine Displacement: 1700cc, 1800cc, 2000cc
• Material: High-temperature, oil-resistant rubber compound
• OEM Reference Number: 021-105-279
• EMPI Part Number: 98-5239-B
• Quantity: Sold Individually
• Placement: Internal Flywheel Hub Groove
• Function: Secondary seal between crankshaft and flywheel mating surface

PRO TIPS

1. Lubrication is Vital for a Proper Seal

Never install this O-ring dry. Before sliding the flywheel onto the crankshaft, apply a thin, even film of clean engine oil or high-quality assembly lube to the O-ring itself. This lubrication prevents the rubber from "rolling," pinching, or tearing as the flywheel is seated over the crankshaft snout. A dry installation often leads to immediate leaks upon the first engine start-up, forcing you to pull the engine all over again. Taking ten seconds to lubricate the seal ensures it slides into place smoothly and maintains its round profile for a perfect seal.

2. Meticulously Inspect the Flywheel Groove

Take the time to thoroughly clean the internal groove of the flywheel where this O-ring resides. Use a lint-free cloth and a shot of brake cleaner to remove any carbonized oil residue, old rubber fragments, or metallic debris. If you notice any burrs or sharp edges in the groove from previous removals, lightly dress them down with a piece of fine-grit emery cloth. A clean, smooth mating surface is the only way to ensure the O-ring can compress evenly and provide a 360-degree barrier against high-pressure oil.

3. The Golden Rule: Replace the Main Seal Simultaneously

In the world of air-cooled VW maintenance, it is considered a cardinal sin to replace the flywheel O-ring without also replacing the rear main seal (crankshaft