2017-2019 Porsche 911 Engine Mounts: PADM Faults, Bracket Numbers, and Replacement Costs

Part Number Confusion: Mount vs. Bracket

It is important to clarify a common point of confusion. The OEM part number 9A2-375-236-02 (and its variants) is for the Engine Mount Support Bracket, not the engine mount itself. This is a sturdy, cast aluminum piece that connects the actual engine mount to the vehicle's frame. While essential, this bracket rarely fails. The engine mount is the more complex component—containing rubber and sometimes electronic parts—that actually wears out.

Standard vs. Dynamic (PADM) Mounts: A Critical Difference

Before diagnosing or buying, you must identify which type of engine mount your 2017-2019 Porsche 911 has. This is the single most important factor affecting symptoms, cost, and repair strategy.

How to Identify Your Mounts:

• Standard Mounts: These are passive, hydraulic mounts. Vehicles without the Sport Chrono package typically have standard mounts.
• Porsche Active Drivetrain Mounts (PADM): These are electronically controlled active mounts. If your car has the Sport Chrono package (with the mode switch on the steering wheel), it almost certainly has PADM. PADM mounts have a visible electrical connector running to them.

Symptoms of a Failing Engine Mount

Failure symptoms differ significantly between the two mount types.

Symptoms of Standard Mount Failure:

• Excessive Vibration: A strong vibration felt in the cabin, floor, or steering wheel, especially at idle or when accelerating.
• Clunking or Thudding Noises: Loud clunks or bangs from the rear of the car during acceleration, deceleration, or gear changes. This is the sound of the engine moving excessively and hitting other components.
• Sagging Exhaust Tips: As the rubber in the mounts degrades and collapses, the entire engine can sag slightly. This is often most visible by looking at the exhaust tips, which may appear lower than normal or uneven.
• Sloppy Drivetrain Feel: A general sense of looseness in the drivetrain, less precise shifting, and a delay in power delivery.

Symptoms of PADM (Dynamic Mount) Failure:

• "PADM Fault" or "PADM Disabled" Message: The most common symptom by far is a warning message on the instrument cluster. This almost always indicates the failure of an internal electronic sensor, not the physical mount structure.
• Reverts to "Soft" Mode: When a PADM fault occurs, the system deactivates, and the mounts default to their softest setting. You may not notice any change in driving feel during normal conditions, but the performance-enhancing stiffening will be disabled.
• Physical Failure (Rare): In rare cases, a PADM mount can fail mechanically like a standard mount. Symptoms would include fluid leaks from the mount housing, visible cracks in the rubber, or the same clunking and vibration as a failed standard mount.

Buying a Used 2017-2019 911 Engine Mount

Purchasing a used engine mount can be a smart way to save money, but careful inspection is critical.

What to Check Before Purchasing:

• For Standard Mounts:
  • Inspect the Rubber: Look for any signs of cracking, perishing, or tearing in the rubber. The rubber should be firm and free of deep cracks.
  • Check for Leaks: These are hydraulic mounts. Check for any signs of fluid residue, which indicates a failed internal seal.
  • Verify Part Number: Ensure the part number (e.g., 99137504904 for a standard mount) matches what your vehicle requires.
• For PADM (Dynamic) Mounts:

  Warning: Buying a used PADM mount is risky. The electronic sensor is a common failure point, and it's impossible to test on a loose part.

  • Assume the Sensor is Bad: It is safest to assume the sensor in a used PADM mount will need to be replaced. Factor the cost of a new aftermarket sensor (around $300) into your purchase price.
  • Physical Inspection: Check for any obvious physical damage, such as cracks in the housing, a damaged electrical connector, or fluid leaks.
  • Why Used OEM is a Good Option: If you can find a physically intact used PADM mount for a low price, you can install a new aftermarket sensor and have a fully functional mount for a fraction of the cost of a new OEM unit.

Known Issues, TSBs, and Recalls

As of early 2026, there are no specific recalls or widespread Technical Service Bulletins (TSBs) from Porsche or the NHTSA regarding engine mount failure for the 2017-2019 Porsche 911 (991.2 generation). The common PADM sensor failure is well-documented in owner forums and by independent specialists but has not resulted in an official recall campaign.

Replacement Overview

Replacing the engine mounts on a 991.2 is a moderately difficult job that requires some disassembly of the rear of the car.

• Difficulty: 3 out of 5
• Estimated Time: 2-3 hours
• Tools Required: E12 Torx socket, 18mm deep socket, extensions, ratchet, torque wrench, floor jack, and a block of wood.
• General Steps:
  1. Access the mounts by removing the rear bumper, taillights, and rear spoiler assembly.
  2. Support the engine from underneath using a floor jack with a wide block of wood to distribute the load across the plastic oil pan. Do not lift the car; just support the engine's weight.
  3. Working from below, remove the 18mm nut securing the mount stud to the carrier.
  4. From above, remove the two E12 Torx bolts holding the mount to the chassis.
  5. If replacing a PADM mount, disconnect the electrical connector.
  6. Remove the old mount and install the new one. It is highly recommended to replace mounts in pairs.
  🎬 See this step-by-step walkthrough for replacing 991.2 engine mounts.
• Torque Specs:
  • Bottom 18mm Nut: 63 ft-lbs (86 Nm)
  • Top E12 Torx Bolts: 27 ft-lbs (37 Nm)

Cost Comparison

The cost difference, especially for PADM-equipped cars, is significant.

Frequently Asked Questions (FAQ)