Oil Pressure Sending Unit Replacement – 2.5L NA

Overview

This procedure outlines the steps to replace the oil pressure sending unit on all Porsche 944 variants with an 8-valve engine, covering pre-1985.5 and 1985.5 onwards models. The oil pressure sending unit monitors engine oil pressure and sends data to the dashboard gauge, ensuring accurate readings to prevent engine damage. This guide is tailored for DIY enthusiasts with mechanical experience, focusing on clear instructions and model-specific details.

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Tools Required

• 24mm (15/16 inch) stubby open end wrench (thin head preferred)
• Metric socket set
• 24mm (15/16 inch) open-ended crow’s foot (for torque wrench, optional)
• Torque wrench
• Jack and jack stands

Parts Required

• Oil pressure sending unit, 944 606 911 00
• M18 x 24mm aluminum or copper crush washer, N 013 849 2

Step-by-Step Procedure

Step 1: Prepare the Vehicle

1. Disconnect the negative battery lead to ensure safety during the procedure.
2. Raise the car using a jack and secure it on jack stands for safe access to the underside.
3. Remove all skid plates or belly pans protecting the bottom of the engine to access the oil pressure sending unit.

Step 2: Access the Oil Pressure Sending Unit

For Pre-85.5 models:
The power steering pump typically does not need to be removed, as there are no additional oil cooler lines obstructing access.
For 85.5 Onwards models:
If an external oil cooler is installed, oil lines may obstruct access. Disconnect the power steering pump (without detaching fluid lines) by removing the belt tension adjusting turnbuckle. Do not alter the turnbuckle’s adjustment to simplify reinstallation. Secure the pump out of the way using a bungee cord or wire.

4. Locate the oil pressure sending unit, positioned just below the oil filter, and disconnect the two wire leads connected to its terminals.

Step 3: Remove and Replace the Oil Pressure Sending Unit

5. Place catch rags or a drip pan under the sending unit to catch any oil that may drip during removal.
6. Using a 24mm (15/16 inch) stubby open end wrench, loosen and remove the oil pressure sending unit. Work quickly to minimize oil loss.
7. Install the new oil pressure sending unit, 944 606 911 00, with a new M18 x 24mm crush washer, N 013 849 2, to ensure a proper seal.
8. Tighten the sending unit to 35 Nm (25 ft-lbs) using a torque wrench with a 24mm (15/16 inch) open-ended crow’s foot. If a crow’s foot is unavailable, tighten until snug without over forcing to avoid damaging the crush washer.

Step 4: Reconnect and Test

9. Reconnect the two wire leads to the terminals of the new sending unit. Ensure correct connection: one terminal is a straight post, and the other typically has a spaded connector. Use the old sending unit as a reference to match the spaded connector to the correct terminal. Incorrect connections may cause the oil pressure gauge to peg high or the low oil pressure light to flicker at idle.
10. Reinstall the power steering pump (if removed) using the original turnbuckle adjustment to maintain belt tension.
11. Reconnect the positive battery lead.
12. Start the car and verify that the oil pressure gauge operates correctly, showing stable readings within the normal range (approximately 2–5 bar at idle and higher under acceleration).

Step 5: Finalize the Procedure

13. Reinstall the belly pans or skid plates removed earlier.
14. Lower the car from the jack stands using the jack.

Post Procedure Checklist

• Check for oil leaks around the new oil pressure sending unit after running the engine for a few minutes.
• Verify that the oil pressure gauge displays stable and accurate readings during idle and acceleration.
• Ensure all tools and debris are removed from the engine bay and under the car.
• Confirm that the belly pans are securely reinstalled and the car is safely lowered.

Sources

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