Exhaust lock nut for bolt. Porsche 964  ❭  99908405202

Exhaust lock nut for bolt, M8.
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Related, superseded, cross reference or alternative numbers for comparison.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