National 99353 Engine Crankshaft Repair Sleeve - Rear

Engine Crankshaft Repair Sleeve for Rear Seal Repair

National 99353 is a stainless steel engine crankshaft repair sleeve used to restore a worn sealing surface at the rear of the crankshaft. It is built for applications where the shaft diameter falls within the specified range and where a precise sleeve fit is needed to help the seal run on a smoother surface.

Compatible With a wide range of BMW, Buick, Chevrolet, GMC, Cadillac, Saab, Porsche, and other rear crankshaft seal applications, this sleeve supports accurate repair work on high-mileage engines. National 99353 is also cross-referenced to KWK99353 for the same application.

• Stainless steel construction for corrosion resistance and durability
• Flanged design with a 4.000 in. outside diameter
• Installation depth: 1.732 in.
• Overall width: 0.665 in.; width on shaft: 0.528 in.
• Shaft size: 3.543 in. with a 3.540-3.546 in. range
• Engine crankshaft repair sleeve for rear seal service
• National 99353 / Part Number 99353

Detailed Product Description

This crankshaft repair sleeve is intended for rear crankshaft seal repair where the original sealing surface has wear, grooves, or surface damage. By providing a new stainless steel sealing surface, it helps restore proper contact for the rear main seal on many import and domestic vehicles, including BMW 328i, BMW X5, Chevrolet Malibu, and Cadillac CTS rear applications. The flanged profile and defined shaft dimensions help support a controlled installation on the crankshaft journal.

National has supplied sealing solutions for decades, and this part reflects that focus on precision fit and material selection. Use the listed shaft diameter, flange diameter, width, and installation depth to confirm application before service. National 99353 is a direct-fit repair sleeve for rear crankshaft seal repair across the listed vehicle coverage.

What It Helps Repair

• Rear main seal leaks caused by a worn crankshaft sealing surface
• Oil seepage from grooves or scoring on the crankshaft journal
• Seal failure after repeated installation on the same shaft area
• Poor seal contact on high-mileage rear crankshaft applications
• Need for a precise repair surface without replacing the crankshaft

Installation Notes and Tips

Verify the crankshaft diameter against the listed 3.543 in. shaft size and the 3.540-3.546 in. range before installation. Clean the shaft thoroughly, inspect for burrs or heavy damage, and confirm that the sleeve seats to the specified installation depth of 1.732 in. For best results, match the sleeve to the rear seal application and confirm any width or outside diameter notes shown in the fitment data, especially on BMW M3, BMW Z4, and other noted configurations.

Quality Assurance

National is recognized for sealing products and engineering support across automotive repair applications. This sleeve is made from stainless steel and built to the dimensional specifications listed above for consistent service in rear crankshaft seal repairs.

• Fits 2014-2019 BMW 640i xDrive Gran Coupe, rear
• Fits 2016-2019 BMW M2, rear
• Fits 2015-2019 BMW M4, rear, with 1.102 in. width; 4 in. outside diameter
• Fits 2019 BMW X6, rear, with 1.102 in. width; 4 in. outside diameter
• Fits 2016-2019 Buick Envision, rear
• Fits 2016-2019 Chevrolet Camaro, rear
• Fits 2015-2019 GMC Canyon, rear
• Fits 2013-2019 Cadillac ATS, rear
• Fits 2001-2007 BMW 530i, rear, with 1.102 in. width; 4 in. outside diameter
• Fits 2001-2005 Lexus IS300, rear, with 1.102 in. width; 4 in. outside diameter