Original BMW Crankcase Breather O-Ring 42.86 x 3.53 mm for BMW 2, 3, 4, 5 Series, X1, X3, X4, X5, and Z4 (2012–2018)

This Original BMW O-ring seals the crankcase breather on the N20 and N26 four-cylinder engines in the 228i, 320i, 328i, 428i, 528i, X1, X3, X4, X5 xDrive40e, and Z4 sDrive28i (2012–2018). BMW sizes the ring at 42.86 x 3.53 mm, and it weighs only 2 g (0.07 oz). The crankcase ventilation system sends blow-by gases from the crankcase back into the intake manifold so they burn in the combustion process. This ring keeps that connection sealed. BMW shows production of this number starting in March 2011. It is made in China and sold individually.

Original BMW Parts carry a 24-month parts warranty.

An O-ring seals by compressing in its groove between two mating parts, which is why the size has to be exact. BMW uses this one ring across the N20 and the N26, the variant fitted to some 228i, 328i, and 428i models. Rear-drive and xDrive cars share it, as do sedans, the 3 Series Gran Turismo, the 4 Series coupe and Gran Coupe, and the four-cylinder X models. The ventilation system also controls how much blow-by escapes the combustion chamber and helps hold crankcase pressure in check. A sound seal at each joint keeps that system working as BMW intended.

Technical Details

• Manufacturer: BMW (Original BMW)
• Part number: 11-12-7-605-329
• BMW part name: O-ring
• Size: 42.86 x 3.53 mm
• Weight: 2 g (0.07 oz)
• Application: engine crankcase breather
• Engines: N20 and N26 four-cylinder
• Production start: March 2011
• Country of manufacture: China
• Sold as: one O-ring
• Warranty: 24-month Original BMW parts warranty

Common Questions

Which engines use this O-ring?
BMW uses it on the N20 and N26 four-cylinder engines.

Does it fit every X5?
No. Among X5 models it is matched only to the xDrive40e plug-in hybrid from 2016–2018, which uses the N20.

Fitment & Compatibility

Check the table below for the exact year, model, submodel, and any listed notes. Send your VIN and PMB Performance will confirm the fit, drawing on more than 20 years in the trade.