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- Porsche 964 (911) C2 1989-93
- Porsche 964 (911) C4 1989-93
This OE match exhaust lock nut is a direct replacement for the original Porsche component used in the exhaust system of the 964 generation 911.
Sold individually,
Fits:
Porsche 964 C2 / C4 1989 - 1994
Diagram ref no 10
This nut is commonly used on exhaust manifolds, heat exchangers, mufflers, and exhaust pipe connections, making it a critical piece of hardware for secure exhaust assembly.
This lock nut secures exhaust components together, ensuring a tight and reliable connection. Its locking design prevents loosening due to vibration and heat cycles, maintaining exhaust system integrity and preventing leaks.
Function
• Secures exhaust system components (manifold, pipes, muffler)
• Prevents loosening under high heat and vibration
• Maintains tight, leak-free exhaust connections
• Withstands extreme temperature conditions
• Allows reliable fastening with long-term durability
Exhaust lock nuts are exposed to extreme heat, corrosion, and constant vibration, which can cause them to seize, degrade, or lose their locking ability. Worn or incorrect fasteners can lead to exhaust leaks, loose components, or difficult disassembly. Replacing them ensures secure fastening and long-term reliability of the exhaust system.
When to replace
• During exhaust repairs or component replacement
• Nut is corroded, seized, or damaged
• Loss of locking function (nut loosens easily)
• Evidence of exhaust leaks at joints
• As part of preventative maintenance on older vehicles
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99908405202
The product you are viewing cross references to these numbers
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
Exhaust Hexagon Head Bolt (Short)
Sold each
Ensure a secure and reliable exhaust installation with this
OE Match Short Exhaust Hexagon Head Bolt.
Manufactured to the original factory specification, this provides the correct strength, thread specification and fit required for
securing exhaust components.
Fits:
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
Diagram ref no 25
Exhaust hardware operates in one of the harshest environments on any vehicle, being subjected to extreme temperatures, vibration, corrosion and repeated heating and cooling cycles. This OE Match bolt is manufactured from high-quality materials to deliver dependable clamping force and long service life, making it ideal for routine repairs, exhaust upgrades or complete engine rebuilds.
What Does the Exhaust Hexagon Head Bolt Do?
The exhaust bolt is a critical fastening component within the exhaust system.
Its primary functions include:
- Securing exhaust components together.
- Maintaining correct clamping force between mating surfaces.
- Preventing exhaust leaks.
- Resisting loosening caused by vibration and thermal expansion.
- Helping maintain proper alignment of exhaust components.
- Supporting reliable long-term exhaust system performance.
Using the correct OE-specification fasteners helps ensure safe and leak-free exhaust operation.
Why Do Exhaust Bolts Need Replacing?
Exhaust bolts are continually exposed to harsh operating conditions.
Common causes of deterioration include:
- Corrosion caused by moisture and road salt.
- Extreme exhaust temperatures.
- Repeated heat cycles causing fatigue.
- Thread damage during removal.
- Seizure due to oxidation.
- Rounded or damaged bolt heads during servicing.
Once removed, older exhaust hardware is often unsuitable for reuse due to corrosion or loss of clamping performance.
When Should They Be Replaced?
Replacement is recommended when:
- Removing or replacing exhaust components.
- Installing new silencers, catalytic converters or manifolds.
- Repairing exhaust leaks.
- The original bolt is corroded or seized.
- Threads are damaged or worn.
- Carrying out engine or exhaust system restoration.
- Performing preventative maintenance during exhaust servicing.
Replacing exhaust hardware whenever the system is dismantled helps ensure reliable sealing and simplifies future maintenance.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90037810501
The product you are viewing cross references to these numbers
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
EACH
Fits:
Porsche 996 C2 / C4 / C4S 1998-05
Porsche 996 GT3 2000-05
Porsche 997 C2 / C4 / C2S / C4S 2005-08
Diagram ref no 24.
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90037818301
The product you are viewing cross references to these numbers
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 C2 3.6L 09/01-2005
- Porsche 996 C4 3.6L 09/01-2005
- Porsche 996 C4S 3.6L 09/01-2005
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 Carrera 2 3.6L 2005-08
- Porsche 997 MK1 Carrera 2S 3.8L 2005-08
- Porsche 997 MK1 Carrera 4 3.6L 2005-08
- Porsche 997 MK1 Carrera 4S 3.8L 2005-08
An OE Match exhaust hexagon nut (M8 size) designed as a self-locking fastener for securing exhaust system components on Porsche 996 and 997 models.
Sold each
Fits:
Porsche 996 C2 / C4 / C4S 1998 - 1905
Porsche 996 GT3 2000 - 2005
Porsche 997 C2 / C4 / C2S / C4S 2005 - 2008
Diagram ref no 16
This hexagon nut secures exhaust system components in place, maintaining tight connections and preventing loosening caused by heat cycles and vibration.
Function
• Secures exhaust components and mounting points
• Provides a self-locking, vibration-resistant fit
• Maintains tight clamping force under heat stress
• Resists corrosion and environmental exposure
• Ensures safe and stable exhaust system assembly
Exhaust fasteners are exposed to extreme heat cycles and corrosion, which can cause nuts to seize, degrade, or lose their locking ability. This can result in exhaust leaks, loose components, or difficulty during removal.
Replacing worn or damaged nuts ensures secure fastening, prevents exhaust system issues, and simplifies future maintenance.
When to replace
• During exhaust repairs or replacement
• Nut is corroded, seized, or rounded
• Loss of locking function or clamping strength
• Evidence of exhaust leaks at joints
• As part of preventative maintenance
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
90038000501
The product you are viewing cross references to these numbers