1973 Porsche 911 Crankshaft Seal Part 999-113-057-52-OEM – The Right Choice

The 1973 Porsche 911 is a classic that demands correct maintenance. One small but critical component is the crankshaft seal, specifically OEM part number 999-113-057-52. Using the right seal prevents oil leaks, protects the engine, and maintains performance. This article explains the seal's function, why the OEM part is essential, and how to approach replacement.

Understanding the Crankshaft Seal in a 1973 Porsche 911

The crankshaft seal sits at the front or rear of the crankshaft, keeping engine oil inside while allowing the shaft to rotate. In a 1973 911 (F-series), the front seal is located behind the fan and pulley, while the rear seal is near the flywheel. Both are vital—if either fails, oil leaks onto the ground or clutch, causing smoke, slipping, or engine damage.

Part 999-113-057-52-OEM is the front crankshaft seal for the 1973 model year. It fits engines with the 2.4L and 2.7L variants common to that era. The seal is a single-lip design with a metal outer shell and a rubber sealing lip, engineered to withstand heat and oil pressure.

Signs of a Failing Crankshaft Seal

• Oil drips from the front of the engine, often near the centerline.
• Oil on the fan, belt, or pulley.
• Low oil level between changes without visible leaks elsewhere.
• Oil smell from the engine bay while driving.

Ignoring a bad seal can lead to oil starvation, belt slippage, or clutch contamination (for rear seals). Replacement is straightforward but requires attention to detail.

Why Choose OEM Part 999-113-057-52?

OEM (Original Equipment Manufacturer) parts are made to Porsche's specifications. For a 1973 car, aftermarket seals may have slightly different dimensions or material composition. The OEM seal ensures:

• Exact fit: The outer diameter, inner diameter, and thickness match the original.
• Correct material: The rubber compound resists oil swelling and high temperature.
• Longevity: Consistent with the original 50+ year design.

Aftermarket seals can work, but many owners report premature leaks due to improper hardness or poor sealing lip geometry. For a car that's often kept for decades, OEM is the safe bet.

Compatibility

Part 999-113-057-52-OEM is specifically for the front crankshaft seal on 1972–1973 911 with 2.4L or 2.7L engines. It may also fit 1974 models with minor differences, but always verify your engine number. The rear crankshaft seal is a different part (999-113-058-52).

Installation Tips for the 1973 Porsche 911 Front Seal

Replacing the front seal requires removing the fan, belt, and pulley. Here's a practical approach:

1. Drain oil – Not strictly necessary, but removing the oil filler cap reduces pressure.
2. Remove fan – Unbolt the fan shroud and fan hub. Note the position of spacer washers.
3. Remove pulley – Use a puller to avoid damaging the crankshaft threads.
4. Pry out old seal – Carefully with a seal puller, avoiding scratches on the crankshaft or housing.
5. Clean sealing surface – Use brake cleaner and a rag. No burrs or old sealant.
6. Install new seal – Lubricate the seal lip with engine oil. Press it in squarely using a seal driver or large socket. The seal should sit flush with the housing edge.
7. Reassemble – Torque pulley bolts to spec (around 50-75 ft-lbs depending on engine).

Common mistakes: driving the seal too deep (blocks oil return), damaging the lip with tools, or forgetting to lubricate. If the seal leaks after installation, it's often due to a scratch on the crankshaft surface—a speedi-sleeve can repair minor wear.

Where to Buy the OEM Seal

Porsche dealerships stock part 999-113-057-52, but you can also order from specialty Porsche parts suppliers. Expect to pay $20–$40. Avoid used seals—they are single-use. Ensure the packaging says "OEM" or "Genuine Porsche." Counterfeit seals exist; inspect the rubber for uniform texture and the part number for correct font.

Final Recommendation

For a 1973 Porsche 911, the crankshaft seal part 999-113-057-52-OEM is the correct and reliable choice. Paying a little more ensures a proper fit and long life. If you're doing the work yourself, follow the steps carefully and use proper tools. If hiring a shop, ask them to use OEM parts. A small seal protects a big investment—don't risk a leak with an unknown aftermarket part.

Maintain your classic 911 with factory-quality components, and it will reward you with miles of driving pleasure.