Front Crankshaft Oil Seal Replacement – 2.5L NA

Overview

This procedure replaces the front crankshaft oil seal on all Porsche 944 variants (8-valve engine) to prevent oil leaks from the crankshaft area. A worn seal can lead to oil loss, which may damage engine components. This guide covers both pre-1985.5 (1982–1984) and 1985.5 onwards (1984–1988) models, with specific distinctions for seal part numbers.

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Tools Required

• Metric wrench set (8mm to 19mm, 5/16 inch to 3/4 inch)
• Metric socket set (8mm to 19mm, 5/16 inch to 3/4 inch)
• Jack stands or ramps
• Floor jack
• Timing belt tension tool (P9201)
• Flywheel lock (P9206)
• Gear puller
• Seal puller

Parts Required

• Crankshaft oil seal (Pre-85.5): 999 113 268 40 (38 x 55 x 7 mm)
• Crankshaft oil seal (85.5 Onwards): 999 113 331 50 (38 x 52 x 7 mm)
• O-ring: 999 707 283 40

Required Additional Procedures

Steps in these procedures are required to complete this process:

• Timing Belt Removal
• Locating and Setting Engine to Top Dead Center (TDC), Cylinder 1
• Timing Belt Installation

Step-by-Step Procedure

Step 1: Prepare the Vehicle

1. Disconnect the negative battery lead to ensure safety during the procedure.
2. Raise the vehicle using a floor jack and secure it on jack stands or ramps for safe access to the engine bay.

Step 2: Remove the Timing Belt

3. Follow this link to ensure this step – Timing Belt Removal – is followed accurately to remove the timing belt.
4. Follow this link to ensure this step – Locating and Setting Engine to Top Dead Center (TDC), Cylinder 1 – is followed accurately to align the engine correctly.

Step 3: Remove Components

5. Remove the rear timing cover by loosening the bolts with a 13mm (1/2 inch) wrench or socket. Torque for these bolts is 10 Nm (7 ft-lbs) when reinstalling.
6. Carefully remove the oil pump thrust washer, O-ring (999 707 283 40), and drive sleeve from the crankshaft.

Step 4: Inspect the Drive Gear

7. Inspect the oil pump drive gear for a ridge or wear, which can prevent proper sealing with the new crankshaft oil seal.

If a ridge or significant wear is present, replace the drive gear. Refer to the Porsche 944 Workshop Manual for drive gear part numbers and replacement instructions.

Step 5: Remove the Old Crankshaft Oil Seal

8. Use a seal puller to carefully remove the old crankshaft oil seal from the oil pump housing. Avoid damaging the housing surface.
9. Clean the seal seating area in the oil pump housing with a lint-free cloth to ensure a smooth surface for the new seal.

Step 6: Install the New Crankshaft Oil Seal

10. Install the new crankshaft oil seal based on your model year:

For Pre-85.5 models:
Use seal 999 113 268 40 (38 x 55 x 7 mm) and press it into the oil pump housing evenly using a seal installer or a socket of similar diameter.

For 85.5 Onwards models:
Use seal 999 113 331 50 (38 x 52 x 7 mm) and press it into the oil pump housing evenly using a seal installer or a socket of similar diameter.

Step 7: Reinstall Components

11. Install the oil pump drive sleeve onto the crankshaft, ensuring proper alignment.
12. Install a new O-ring (999 707 283 40) and the oil pump thrust washer onto the crankshaft.
13. Reinstall the rear timing cover and tighten the bolts to 10 Nm (7 ft-lbs) using a 13mm (1/2 inch) wrench or socket.

Step 8: Reinstall the Timing Belt

14. Follow this link to ensure this step – Timing Belt Installation – is followed accurately to reinstall the timing belt.
15. Adjust the timing belt tension according to the Porsche 944 Workshop Manual.

Step 9: Finalize the Procedure

16. Lower the vehicle from the jack stands or ramps using a floor jack.
17. Reconnect the negative battery lead.

Post Procedure Checklist

• Verify that the engine is set to Top Dead Center (TDC) and the timing belt is correctly aligned.
• Check that all tools and debris are removed from the engine bay.
• Inspect the oil pump drive sleeve and new seal for proper alignment and seating.
• Start the engine and check for oil leaks around the crankshaft seal area.
• Drive the vehicle for 5 miles (8 km) and recheck for leaks or abnormal noises.

Sources

• Clark’s Garage
• Pelican Parts
• Porsche 944 Workshop Manuals
• YouTube