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Oil Separation & Breather System for BMW Z3 (1996-2002)

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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 (8)

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Comprehensive Constant Pressure Valve Replacement Kit

T#:557341

Part#: 11111318185TMSKT

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05-03-2026

$ 84.32 USD

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When your CPV O-ring fails it causes a slow oil leak on the passenger side of the engine, making an oily mess that frequently resembles a rear main seal leak. Replacing the CPV with an upgraded o-ring ensures a long-term solution to this common problem.

The factory o-ring over time fails from heat cycling and oil exposure due to the Buna rubber used in OEM o-rings, while the included Viton Fluoroelastomer is resistant to a much higher temperature to ensure prolonged life without leaking.

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Bav Auto Crankcase Pressure Regulator Valve - BMW M52 M54

For vehicles with production date from 09/1998

T#:640207

Part#: 11617501566

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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

For vehicles with production date from 01/2000 For vehicles with production date up to 01/2000

T#:638072

Part#: 11617504536

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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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Bav Auto Vent Hose - From Valve Cover to Oil Separator - E36 E39 Z3 ...

For Model year 1998-2001 only

T#:579869

Part#: 54546

Ships on Aug 11, 2026

Sale - Save 20% $ 26.99

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Performance Oil Separator Kit - M52/S52

For vehicles with production date up to 09/1998

T#:51356040

Part#: 059015LA02KT2KT

Ships on Oct 5, 2026

Sale - Save 19% $ 104.99

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

$ 84.77 USD

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On M52/S52-equipped BMWs, the factory crankcase ventilation (CCV) system is a notorious weak link. Between brittle plastic corrugated hoses that crumble from heat soak and an internal cyclone diaphragm prone to tearing, a failing CCV leads to massive oil consumption, vacuum leaks, and that dreaded "howling" whistle.

This kit addresses these issues with all new components and hardware. Both oil separator hoses, the cyclone separator itself, the mounting grommet, and the retaining bolts are included. Servicing this system is guaranteed to restore performance lost as a result of worn CCV components.

Kit includes:

Cyclone Separator/Crankcase Pressure Regulator Valve High Performance Silicone Breather Hose Return Hose Mounting Grommet Hex Bolt (3)

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Crankcase Breather Hose - E46 M3 01-04 Z3M - S54

T#:12911

Part#: 11157831311

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Sale - Save 8% $ 99.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 92.05 USD

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This hose directs the oil & combustion vapors from the valve cover and directs them to the intake manifold where they are put through combustion again in order to reduce emissions. We recommend replacing this hose when replacing the oil separator #11157840446.

This item fits the following BMWs:
2001-2004 E46 BMW M3
2001-2002 Z3 BMW M Roadster M Coupe

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ECS Tuning Baffled Oil Catch Can - 8oz

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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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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Genuine BMW Crankcase Ventilation Dipstick Hose

For use in cold climates

T#:348228

Part#: 11157532629

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Sale - Save 8% $ 38.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 35.88 USD

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Genuine BMW Vacuum Hose - E36 318ti 318is 318ic 318i M44 1.9L ...

T#:37499

Part#: 11731435862

Special Order: No Guaranteed ETA

Sale - Save 24% $ 29.99

MSRP stands for Manufacturer's Suggested Retail Price. This is the suggested retail price provided by the manufacturer, supplier or seller.

$ 22.93 USD

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05-02-2026

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Genuine BMW Hose - 470mm
This item fits the following BMW Chassis:
E36

Fits BMW Engines including:
M44

Oil Separator Hose - E46, Z4

T#:579880

Part#: 55080

In Stock

Sale - Save 20% $ 24.99

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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.

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

For vehicles with production date up to 10/2003 For vehicles with production date from 01/2000

T#:640502

Part#: 11617504535

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05-03-2026

$ 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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3 Pin Connector

T#:33412930

Part#: 12521706096

In Stock

Sale - Save 11% $ 10.99

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

$ 9.78 USD

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$ 10.99

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$ 9.78 USD

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Includes connector housing with terminals and seals. Commonly used for the idle air control valve (IACV).

ECS Tuning replacement harness connectors include all necessary pins and wire seals for a complete harness repair. Whether you have a broken harness connector or need a complete wiring repair, we have the components you need.

Each connector includes an additional terminal in case one becomes lost or damaged during installation.

*OEM cross reference PN# 12521706096 - Commonly used for the idle air control valve (IACV).

Please reference the original part number from the existing connector to confirm fitment, before ordering.

Suggested tools:

Suggested crimping pliers: T#387193
Wire De-pin tools:
12pc De-Pin Tool Set - T#386379
23pc De-Pin Tool Set - T#641943

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- CCV/PCV Breather Hoses (8)

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