The part number 5WK50136 refers to an ignition coil commonly used in several Porsche models, as well as some Audi and Volkswagen vehicles. For Porsche owners, this ignition coil is a critical component that can affect engine performance, fuel economy, and drivability. This guide explains what part 5WK50136 is, which vehicles it fits, how to recognize when it needs replacement, and practical advice for sourcing and installing a new one.
What Is Porsche Part 5WK50136?
Part 5WK50136 is an ignition coil manufactured by Bosch, the original equipment supplier for many Porsche ignition systems. It is a pencil-style coil designed to sit directly on top of each spark plug, eliminating the need for spark plug wires. In Porsche applications, this coil is used primarily in the M96 and M97 flat-six engines found in the 996 and 997 generations of the 911, as well as the Boxster and Cayman (986 and 987 models).
Specifications and Compatibility
- Coil Type: Pencil (stick) coil with an integrated connector.
- Primary Resistance: Approximately 0.5 ohms.
- Secondary Resistance: Approximately 6–8 kOhms.
- Output Voltage: Up to 40 kV.
- Connector: 3-pin (power, ground, signal).
- Interchangeable Part Numbers: Also sold as Bosch 0221504036, and cross-references with Denso and Beru coils.
Compatible Porsche Models (engine codes):
- 911 (996) 1998–2005 – M96.01, M96.02, M96.03, M96.04
- 911 (997) 2005–2008 – M97.01, M97.02
- Boxster (986) 1996–2004 – M96.20, M96.22, M96.23
- Boxster (987) 2005–2008 – M97.20, M97.21, M97.22
- Cayman (987) 2006–2008 – M97.21, M97.22
- Cayenne (955/957) 2003–2010 – Some V6 and V8 engines may use a different coil; verify.
Note: The 5WK50136 is not used in the 991 generation or later models, which employ updated ignition systems.
Signs of a Failing Ignition Coil
Ignition coils in these Porsche engines can degrade over time due to heat and electrical stress. Common symptoms of a failing 5WK50136 coil include:
- Misfires under load: The engine stutters or hesitates when accelerating, especially uphill or when the engine is warm.
- Rough idle: The engine shakes or runs unevenly at idle, sometimes accompanied by a blinking check engine light.
- Loss of power: Acceleration feels sluggish, and the engine may not rev smoothly.
- Check engine light codes: P0300–P0306 (random or cylinder-specific misfires). A scan tool will often point to a particular cylinder, but coils can fail intermittently.
- Poor fuel economy: A misfiring coil causes incomplete combustion, wasting fuel.
- Backfiring or exhaust popping: Unburned fuel ignites in the exhaust system.
If you experience any of these, it's wise to inspect the ignition coils. Because these coils are mounted directly over the spark plugs, heat from the engine can cause the internal insulation to break down over time, typically after 60,000 to 80,000 miles.
Replacement Considerations
OEM vs Aftermarket
Porsche part 5WK50136 is an OEM Bosch coil. For replacements, you have two main options:
- OEM (Bosch): The same as original equipment. These are reliable but can be more expensive, often $60–$90 per coil from a dealership or independent parts supplier.
- Aftermarket: Brands like Beru, Denso, or Delphi offer coils that meet or exceed OEM specs. Some aftermarket coils may have improvements such as better heat resistance. Prices range from $30–$60 per coil.
Neither option is inherently bad, but cheap unbranded coils often fail prematurely. Stick with well-known manufacturers.
How Many Coils to Replace
These engines have six individual coils (one per cylinder). If one fails, it's common practice to replace all six at once. This prevents future failures and ensures even performance. Replacing only the failed coil is possible, but the remaining coils are likely near the end of their lifespan.
Installation Tips
Replacing the 5WK50136 coils is a manageable DIY task for someone with basic mechanical skills. Here's a brief overview:
- Safety: Disconnect the battery negative terminal. Allow the engine to cool.
- Access: Remove the engine cover (on a 911, access is from the rear; on Boxster/Cayman, access is behind the seats). You may need to remove the air cleaner assembly for easier access to the coils on the right bank.
- Unplug: Disconnect the electrical connector on each coil.
- Remove coil bolt: A single 10mm bolt holds each coil in place. Remove and set aside.
- Pull coil: Gently twist and pull the coil straight up. If it's stuck, use a slight rocking motion. Do not use a pry bar against the valve cover.
- Inspect spark plug: While the coil is out, check the spark plug condition and replace if needed (recommended every 60,000 miles).
- Install new coil: Apply a small amount of dielectric grease to the inside of the coil boot to prevent moisture. Push the new coil firmly onto the spark plug, secure the bolt, and reconnect the harness.
- Repeat for all cylinders. Label each coil's location if you're not replacing all.
- Reassemble and reconnect battery. Start the engine and check for smooth operation.
Torque: Tighten the coil bolt to 8 Nm (6 ft-lb) – do not overtighten.
Where to Buy
Purchase part 5WK50136 from a reputable auto parts retailer, a Porsche dealer, or an online specialist that sells genuine Bosch parts. Avoid unknown sellers on online auction sites unless you can verify authenticity. Counterfeit coils may fail quickly and cause engine damage.
Conclusion and Recommendation
Part 5WK50136 is a critical component for many Porsche 911, Boxster, and Cayman models from the late 1990s through the mid 2000s. Recognizing the symptoms of a failing coil and performing a timely replacement can restore engine performance and prevent more costly repairs. For most owners, replacing all six coils at once with a trusted brand like Bosch or Beru is the best approach. The job is straightforward with basic tools and can be completed in about an hour. Always use high-quality parts and follow proper installation procedures to ensure many miles of reliable driving.