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Porsche // 996 (911) (1997-2005) // 996 GT3 MKI 1999-02
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Stud for Exhaust Manifold - M8x30, L: 45mm - for Porsche 911 Carrera 3.2L 1984-89 & 911 (930) / 964 Turbo 1978-94 - 99906223903
99906223903/1
Vehicle Group
- Porsche 911 1984-1986 3.2L
- Porsche 911 1987-1989 3.2L G50
- Porsche 911 1975-1977 3.0L Turbo (930)
- Porsche 911 1978-1989 3.3L Turbo (930)
- Porsche 964 (911) TURBO 3.3L 1991-93
- Porsche 964 (911) TURBO 3.6L 1991-93
Information
Stud - M8 x 30 / 45mm - which is used to mount the heat exchanger.
This exhaust manifold stud is a high-strength threaded stud used to secure the exhaust manifold (heat exchanger) to the cylinder head on classic air-cooled Porsche 911, Turbo (930), and 964 Turbo models.
Sold individually, 12 required per engine.
Fits:
Porsche 911 Turbo (930) 1978 - 1989
Porsche 911 Carrera 3.2L 1984 - 1989
Porsche 964 Turbo 3.3L 1991 - 1992
Porsche 964 Turbo 3.6L 1993 - 1994
Diagram ref. no. 5A
The exhaust manifold stud forms a critical fastening point that holds the exhaust manifold (or heat exchanger) firmly to the engine’s cylinder head. It ensures the exhaust system components remain tightly seated under heat, vibration, and thermal cycling, preventing exhaust leaks and preserving engine performance.
This stud’s threaded design enables secure engagement with corresponding nuts and manifold flanges. By maintaining proper clamping force, it helps support the manifold gasket and metal mating surfaces, sustaining a leak-free joint under extreme exhaust temperatures and repeated heating/cooling cycles.
Exhaust studs undergo intense heat and stress, which over time can lead to stretching, thread wear, or breakage. A compromised stud can allow exhaust leaks, reduce engine efficiency, and make future removal of the manifold difficult. Replacing them restores correct fit, proper torque retention, and long-term exhaust system reliability.
When to replace:
• Studs show corrosion, thread wear, or distortion
• One or more studs have broken during removal
• Exhaust leak noises at the manifold flange
• During manifold gasket replacement
• Preventive renewal during engine or exhaust overhaul
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99906223903
The product you are viewing cross references to these numbers
This exhaust manifold stud is a high-strength threaded stud used to secure the exhaust manifold (heat exchanger) to the cylinder head on classic air-cooled Porsche 911, Turbo (930), and 964 Turbo models.
Sold individually, 12 required per engine.
Fits:
Porsche 911 Turbo (930) 1978 - 1989
Porsche 911 Carrera 3.2L 1984 - 1989
Porsche 964 Turbo 3.3L 1991 - 1992
Porsche 964 Turbo 3.6L 1993 - 1994
Diagram ref. no. 5A
The exhaust manifold stud forms a critical fastening point that holds the exhaust manifold (or heat exchanger) firmly to the engine’s cylinder head. It ensures the exhaust system components remain tightly seated under heat, vibration, and thermal cycling, preventing exhaust leaks and preserving engine performance.
This stud’s threaded design enables secure engagement with corresponding nuts and manifold flanges. By maintaining proper clamping force, it helps support the manifold gasket and metal mating surfaces, sustaining a leak-free joint under extreme exhaust temperatures and repeated heating/cooling cycles.
Exhaust studs undergo intense heat and stress, which over time can lead to stretching, thread wear, or breakage. A compromised stud can allow exhaust leaks, reduce engine efficiency, and make future removal of the manifold difficult. Replacing them restores correct fit, proper torque retention, and long-term exhaust system reliability.
When to replace:
• Studs show corrosion, thread wear, or distortion
• One or more studs have broken during removal
• Exhaust leak noises at the manifold flange
• During manifold gasket replacement
• Preventive renewal during engine or exhaust overhaul
Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.
99906223903
99906223902
99906223903
The product you are viewing cross references to these numbers
Price: £3.50
In stock
Related products
Vehicle Group
- 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
Information
Exhaust hexagon head bolt (LONG). M 8 x 140.
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
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
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90037818301
90037818301
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Price: £5.92
In stock
Vehicle Group
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- Porsche 996 C2 3.4L 1997-08/01
- Porsche 996 C4 3.4L 1997-08/01
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche 997 MK1 GT3 / GT3 RS 2007-09
- Porsche 997 MKII GT3 / GT3 RS 2010-11
Information
Exhaust manifold bolt. M8 x 28.
EACH
Fits:
Porsche 986 Boxster 1997-04
Porsche 996 C2 / C4 3.4L >>2001
M96.01, M96.02, M96.03,
Porsche 996 GT3 / GT3 RS 2000-05
Porsche 997 GT3 2007-10
Click 'Zoom in' for large parts diagram.
Diagram ref no 4.
Related reference numbers
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90037813100
The product you are viewing cross references to these numbers
EACH
Fits:
Porsche 986 Boxster 1997-04
Porsche 996 C2 / C4 3.4L >>2001
M96.01, M96.02, M96.03,
Porsche 996 GT3 / GT3 RS 2000-05
Porsche 997 GT3 2007-10
Click 'Zoom in' for large parts diagram.
Diagram ref no 4.
Related reference numbers
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90037813100
90037813100
The product you are viewing cross references to these numbers
Price: £3.25
In stock
Vehicle Group
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- 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
Information
Exhaust manifold to catalytic converter bolt
M8 x 35. EACH
Fits:
Porsche 986 Boxster 1997-05
Porsche 996 C2 / C4 / C4S 1997-05
Porsche 996 GT3 1999-05
M8 x 35. EACH
Fits:
Porsche 986 Boxster 1997-05
Porsche 996 C2 / C4 / C4S 1997-05
Porsche 996 GT3 1999-05
Price: £6.38
In stock
Vehicle Group
- Porsche Boxster 986 2.5L 1997-99
- Porsche Boxster 986 2.7L 1999-02
- Porsche Boxster S 986 3.2L 1999-02
- Porsche Boxster 986 2.7L 2003-04
- Porsche Boxster S 986 3.2L 2003-04
- 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 TURBO 2000-05
- Porsche 996 GT3 MKI 1999-02
- Porsche 996 GT3 MKII 2003>>
- Porsche 996 GT3 RS 2003-04
- Porsche Cayman 2.7L 987C 2006-08
- Porsche Cayman S 3.4L 987C 2005-08
Information
Exhaust Manifold to Catalytic Converter Nut.
M8. EACH
Fits:
Porsche 986 Boxster 1997-05
Porsche 987C Cayman 2005-08
Porsche 996 C2 / C4 / C4S 1997-05
Porsche 996 GT3 1999-05
Related reference numbers
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99908405202
The product you are viewing cross references to these numbers
M8. EACH
Fits:
Porsche 986 Boxster 1997-05
Porsche 987C Cayman 2005-08
Porsche 996 C2 / C4 / C4S 1997-05
Porsche 996 GT3 1999-05
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99908405202
99908405202
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Price: £2.15
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