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Oil Separation & Breather System for BMW Z Series E85/6 (2003-2008)

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Every car has a crankcase vent system that is supposed to suppress oil from making it into the intake ports and combustion chamber. A good functioning system will separate oil from the atmosphere and return it to the oil pan (or collect it in a catch can) while allowing the leftover vapors to burn in the combustion chamber or recirculate through the system. This has always been known as a PCV system (Positive Crankcase Ventilation) but BMW has several other names for it - oil separator, crankcase vent (CCV), and cyclonic separator. Failures in the system will allow raw oil to enter the intake and eventually into the engine itself which can have disastrous effects on engine performance and longevity. As emissions regulations on oil and gas venting have gotten more stringent the PCV systems have gotten more complex and failure prone. And because the CCV is intertwined with other systems you could experience rough running, loss of power, higher oil consumption, misfiring, stalling, or other annoying issues. There is no replacement interval for these so we recommend inspecting your crankcase vent system as part of your regular maintenance routines. Symptoms of a bad crankcase vent are: whitish or yellowish film on the underside of the oil cap, whistling/squealing noises (not caused by a belt), suction on the oil cap that makes it hard to unscrew, large amounts of white smoke from the exhaust, and excessive oil consumption.

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CCV/PCV Breather Hoses (5)

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Upgraded Silicone CCV Hose - (11157522931) - N52

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T#:46203577

Part#: 058973LA02

In Stock

$ 101.99

This product was last offered at the strikethrough price on
06-24-2026

$ 78.99 USD

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Due to weak plastic construction, the factory plastic crankcase ventilation breather hose is known to fail. After years of exposure to piping-hot engine bay temperatures and chemical-laden oil vapors, the corrugated plastic tubing can crack, crumble, or fail altogether.

We set out to bulletproof your N52 CCV system with a durable silicone breather hose, designed to provide a comprehensive upgrade and permanent replacement for the factory plastic hose. By replacing the flimsy, heat-hardened OEM plastic hose with a four-ply fluorosilicone hose, you'll experience peace of mind knowing your N52 is free from the inevitable return of oil leaks, vacuum leaks, and drivability concerns that would have been.

This breather hose is found at the front of the engine, and is used to connect the oil separator to the valve cover. It replaces OEM part number 11157522931.

Features:

Silicone construction ensures a durable replacement that is sure to outlast OE plastic
Designed as a direct replacement for the factory breather hose
Retains heating function and OE electrical connector
Design:

Four-ply wire-reinforced fluorosilicone hose is designed to resist degradation due to exposure to oil vapors
O-rings are pre-installed in OE connectors for a lasting seal
Includes pre-installed zinc-coated hose clamps for durability and corrosion resistance
Product Development:

Our Silicone CCV Hose Upgrade was designed, engineered, tested, and quality inspected by our Research and Development team in our Wadsworth, Ohio, facility. We strive for the highest level of precision and quality through leading-edge product development technology, including FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modelling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.

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Crankcase Oil Separator Repair Kit - E85 Z4 2.5i 3.0i 2003-2006 ...

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T#:2895

Part#: 11617533400-E85

Ships in 1-2 days

Sale - Save 5% $ 406.99

This product was last offered at the strikethrough price on
05-03-2026

$ 386.64 USD

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Sale - Save 5%

$ 406.99

This product was last offered at the strikethrough price on
05-03-2026

$ 386.64 USD

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This Crankcase Vent / Oil Separator Repair Kit includes the updated oil separator valve, oil dipstick guide tube and hoses. This kit fits E85 Z4 2.5i Z4 3.0i 2003-2005.

This item fits the following BMWs:
2003-2006 E85 BMW Z4 2.5i Z4 3.0i

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Turner Motorsport Silicone Oil Separator Hose Upgrade (11617559530) -...

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T#:46203579

Part#: 058981LA02

In Stock

$ 101.99

This product was last offered at the strikethrough price on
06-14-2026

$ 59.99 USD

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$ 59.99 USD

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Due to weak plastic construction, the factory plastic crankcase ventilation breather hose is known to fail. After years of exposure to piping-hot engine bay temperatures and chemical-laden oil vapors, the corrugated plastic tubing can crack, crumble, or fail altogether.

Upgrade your N52 CCV system with this durable silicone oil separator hose, designed to provide a comprehensive upgrade and permanent replacement for the factory plastic hose. By replacing the flimsy, heat-hardened OEM plastic hose with a four-ply fluorosilicone hose from Turner Motorsport, you'll experience peace of mind knowing your N52 is free from the inevitable return of oil leaks, vacuum leaks, and drivability concerns that would have been.

This hose is located underneath the intake manifold and is used to connect the oil separator to the induction tract. It replaces OEM part number 11617559530.

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Bav Auto Crankcase Pressure Regulator Valve - BMW M52 M54

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T#:640207

Part#: 11617501566

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Sale - Save 20% $ 32.99

This product was last offered at the strikethrough price on
05-03-2026

$ 26.39 USD

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$ 32.99

This product was last offered at the strikethrough price on
05-03-2026

$ 26.39 USD

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BMW has an ongoing issue with oil separators freezing in cold weather if driving is done before the vehicle is fully warmed up. There is often a howling noise followed by numerous oil leaks. The crankcase breather valve is used to purge the oil vapor from the engine block into the valve cover. However, sometimes condensation can cause it to freeze, causing the entire oil separator system to fail, crack, and disintegrate. Replace this and all the other components of the oil separator system to prevent damage to all the aspects of your engine. As long as you have everything off, you can rest assured that new parts will last and be reliable. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Bav Auto Crankcase Ventilation Return Hose - E46 E39 E60 Z3

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T#:638072

Part#: 11617504536

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Sale - Save 20% $ 26.99

This product was last offered at the strikethrough price on
05-03-2026

$ 21.59 USD

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This is the BMW crankcase return line that goes from the intake manifold to the top CCV connecting hose. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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ECS Tuning Baffled Oil Catch Can - 8oz

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T#:13496655

Part#: 003779ECS05-02

In Stock

Sale - Save 10% $ 238.99

This product was last offered at the strikethrough price on
06-14-2026

$ 215.09 USD

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$ 215.09 USD

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Upgrade Your BMW with ECS Baffled Oil Catch Can

Modern emission regulations require a closed PCV/Breather system for cleaner operation. However, inefficient oil particle capture can lead to excessive oil vapor ingestion, causing carbon buildup, reduced performance, and fuel economy. ECS Tuning's updated ECS Baffled Oil Catch Can, now with an easy-to-empty 1/4" drain fitting, is engineered to collect toxic blow-by gases, minimize carbon deposits, and reduce oil contamination within engine oil. Recirculating oil vapor ensures emissions compliance without venting to the atmosphere.

Key Features:
Highly Efficient Oil Separator: Strategically positioned 4 chamber baffle system maximizes oil/air separation and minimizes oil droplets in the intake tract.
Integrated Dipstick: Knurled and black anodized oil dipstick simplifies oil volume inspection.
Reservoir: Available in 6oz or 8oz capacity with a 1/4" NPT drain plug fitting.
Serviceable: Easily removable baffle plates and drain plug for cleaning.
Easy/Customizable Installation: Combine with the ECS Universal Bracket Kit for simplified installation and adjustable mounting locations.
Leak-Free Fittings: Machined -10AN ORB (O-Ring Boss) fittings available for secure connections (fittings sold separately).

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Bav Auto Upper Oil Separator Vent Tube - E36 E46 E60 E84 Z3 Z4 M54 M5...

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T#:640502

Part#: 11617504535

In Stock

Sale - Save 20% $ 24.99

This product was last offered at the strikethrough price on
05-03-2026

$ 19.99 USD

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This product was last offered at the strikethrough price on
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$ 19.99 USD

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Runs from the top of the oil separator up to rear of the intake manifold. From 1974 to 2019, Bavarian Autosport was one of the premier vendors for BMW and MINI auto parts. We are happy to preserve the Bav Auto legacy by continuing to carry their high-quality products into the future. All Bav Auto parts will remain unchanged in design and sourced from the same OEM suppliers to ensure long-lasting reliability. We trust these parts, accessories, and upgrades so confidently that we back every Bavarian Autosport branded component with a 2-year warranty.

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Oil Separator Hose - E46, Z4

affirm Starting At 0% APR - Subject To Eligibility. See Lending Terms

T#:579880

Part#: 55080

In Stock

Sale - Save 20% $ 24.99

This product was last offered at the strikethrough price on
05-03-2026

$ 19.99 USD

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Sale - Save 20%

$ 24.99

This product was last offered at the strikethrough price on
05-03-2026

$ 19.99 USD

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Cold climate version for extra insulation! Fits all E46 and Z4 chassis equipped with an M54 engine.

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