DIY: How To Replace the Oil Level Sensor On An Air-cooled Porsche 911
If your car has an erratic or non-functional oil level gauge, its probably time to replace your oil level sensor in the oil tank.
Note: The following information is for educational use only. Before proceeding please read my disclaimer page.
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Your air-cooled Porsche 911 has a very large quantity of oil to help with engine cooling duties. Depending on the year it can contain anywhere between 8-14 quarts of oil. Therefore it is critical to maintain a proper level of oil in the tank. Old age and high mileage can lead to the failure of the oil level sender in the tank. This can cause the needle on the oil level gauge to jump around randomly and even fail altogether. Replace the oil level sender with this quick DIY and restore your 911’s oil gauge function.
Model Years Applicable:
All Porsche 911 models up to 1989, excluding 1972. 1972 has a different style oil tank and a more complicated replacement procedure so it will not be covered here.
Note: You do not need to drain the oil tank to replace the sensor if you keep the car level. However some oil may dribble out of the tank when you remove the sensor.
Tools Needed:
- Metric wrench set
- Paper towels (for oil spill cleanup)
- Oil drain pan (to catch drips)
- Rubber gloves
- Safety glasses
- Degreaser
- Plastic trim removal tool
Parts Needed:
- Oil tank level sensor
- 90164154100 (1972 and earlier)
- 91164154102 (1973 and later)
- Oil tank level sensor gasket (all years; if not included with sensor)
- 5 new sealing washers
Caution: Oil is carcinogenic so wear rubber gloves, long sleeves, and safety glasses to protect your skin.
Procedure
Note: The engine oil level can only be checked accurately using the dipstick, when the engine is at operating temperature, running, and idling. This is described in step 6 of this procedure. The dash oil gauge is only a reference. Verify your car has the correct oil level before removing the oil level sensor.
Step 1: Remove Right Rear Wheel
Put your parking brake on, chock the left wheels, and lift the right side of the car using Step 2B of this procedure. Lift just enough to remove the right rear wheel and put a jack stand under that corner of the car to keep it elevated as if the wheel were installed.
Looking into the wheel well, locate the oil tank under the rear right corner of the car. On the flat surface of the oil tank you will see a small circular plate with 2 wires connected to it. This is the oil tank level sensor.
Step 2: Clean Surrounding Area
If your car has not had regular maintenance or has very high miles, the oil tank is probably very dirty from oil leaks and exposure to road debris. Before removing the oil tank level sensor, clean the area around the plate as well as the plate itself to prevent any debris from getting inside the tank opening. Be careful not to damage the wires connected to the plate.
Take note of the orientation of the sensor plate terminals and wires with respect to the oil tank so that they can be re-installed the same way.
Step 3: Remove Old Sensor
Carefully disconnect both wires from the plate terminals. Using a wrench, carefully loosen and remove the 5 nuts and sealing washers from the plate mounting studs. One of the terminals is attached to a stud and will come off as well. Set the nuts, washers, and terminal aside for later reuse.
Using a plastic trim tool, gently pry around the edge of the plate all the way around to release it from the gasket underneath it. The old gasket may come off in pieces due to old age.
Once the plate is released, carefully begin to pull the assembly out of the tank. Once you have the main body (attached to the back of the plate) out, you will need to rotate the whole unit to maneuver the wire arm and the float out of the tank opening. Do not pull on the assembly if it gets hung up inside the tank. Have paper towels ready to catch any oil drips.
If it still will not come out of the tank, try removing the dipstick under the oil tank cap, just in case it is partially hung up.
Step 4: Remove Old Gasket Material
Using the plastic trim tool or a plastic scraper, scrape off any pieces of gasket material stuck to the oil tank opening. Do not drop any pieces inside the tank. Clean the back side of the sensor plate of any old gasket material as well. Wipe both mating surfaces on the tank and sensor plate clean.
Step 5: Install New Gasket and Sensor
Compare the hole-pattern in your new gasket to the hole-pattern in the sensor mounting plate. Notice that 2 holes are spaced further apart than the rest. This controls the installation orientation of the sensor in the tank. New gaskets will commonly have a notch in them to identify the 2 holes that are furthest apart. They are made of either rubber or cork.
Install the new gasket with the holes spaced furthest apart over the oil tank studs with the same spacing. Push the gasket all the way down against the tank surface.
Insert the new oil level sensor into the tank starting with the float, then rotating it completely inside the tank.
Rotate the sensor plate so that the 2 holes spaced furthest apart go over the corresponding tank studs.
Gently press the sensor plate down against the gasket.
As during removal of the old sensor, if it gets hung up on something inside the tank, try pulling the dipstick underneath the oil tank cap and put it back in once the sensor is fully seated against the gasket.
Install new sealing washers and re-install the old nuts finger tight. Note which stud originally had the removable ground terminal and put it back in its original location.
Slowly tighten the nuts in a star pattern until they are snug. Reconnect the wires to the sensor terminals as they were before.
Start the car and the oil level gauge needle should now flip to life. After running the engine, if any minor oil leakage occurs around the sensor plate, tighten the nuts a bit more.
Oil Level Sensor installation is now complete.