N-908-946-01 Genuine VW/Audi Exhaust Manifold Self-Locking Nut - M8 x 1.25

Genuine VW/Audi exhaust manifold self-locking nut, part number N-908-946-01. This original M8 x 1.25 nut retains the exhaust manifold at its assigned cylinder-head stud connection on the configurations below. One nut is supplied.

Technical details

• Original number: N-908-946-01 / N90894601.
• Published nominal thread size: M8 x 1.25.
• Self-locking hex nut with a shoulder beneath the wrenching flats.
• Assigned application: factory exhaust manifold-to-cylinder-head mounting hardware.
• Cataloged as non-reusable hardware; renew after removal.
• Stud, manifold gasket, manifold and other exhaust hardware are separate.

The nut clamps the manifold at its assigned stud attachment. Correct hardware and the specified gasket form part of the complete exhaust connection. The nut itself is not the sealing gasket and cannot compensate for a damaged mating surface.

Nearby turbocharger and downpipe connections can use different nut sizes and hardware. Match this original number to the actual manifold stud. Do not substitute it at another exhaust joint solely because the nut appears similar.

Common reasons to replace

Replace the nut after removal during manifold or turbocharger service, in accordance with its cataloged non-reusable status and the applicable factory procedure. Obtain the required quantity for every attachment disturbed during the repair.

Replace missing hardware, damaged threads, rounded wrenching flats, deformation or corrosion that prevents proper installation. Exhaust heat and earlier repair work can leave damaged fasteners or mating studs that must be inspected before reassembly.

Exhaust leakage, noise or a loose manifold requires diagnosis of the gasket, manifold, studs, cylinder-head attachment and supporting components. A new nut cannot repair a cracked manifold, broken stud, stripped thread or distorted sealing surface.

Correct the diagnosed defect and inspect the complete mounting connection. Using excessive tightening force to conceal a leak can damage the fastener or associated components.

Installation and service notes

Follow the factory manifold procedure for the exact engine. Allow the exhaust assembly to cool and perform the prescribed access, support and disconnection steps before releasing the mounting hardware.

Inspect the cylinder-head mounting studs, mating faces and manifold. Correct damaged threads or components before installing new hardware. Use the correctly specified gasket and position the manifold at its assigned mounting points.

Start the new nut by hand on an undamaged stud without cross-threading. Verify that the manifold and gasket are seated correctly before tightening. Do not use the nut to force a misaligned assembly into position.

Use the correct hex tool and follow the factory tightening sequence, torque and any additional angle for the manifold-to-head attachment. Apply thread preparation, lubricant or anti-seize only when the applicable procedure specifies it.

Do not transfer a tightening value from a turbocharger outlet flange, downpipe connection or another M8 fastener. The same nominal thread size does not establish the correct tightening method.

Complete the required reassembly, exhaust clearance and leakage checks. Confirm that all serviced mounting positions have the prescribed hardware and the connected exhaust components are supported correctly.

This listing supplies one original nut, not a complete manifold installation kit. Select studs, gaskets and additional hardware separately for the repair.

Fitment

Confirm original N90894601 at the manifold-to-head attachment before ordering. One nut supplied.