Oil Separation & Breather System for BMW 3 Series E46 (1999-2005)

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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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Bav Auto Crankcase Pressure Regulator Valve - BMW M52 M54

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T#:640207

Part#: 11617501566

In Stock

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This product was last offered at the strikethrough price on
11-07-2026

$ 23.09 USD

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$ 32.99

This product was last offered at the strikethrough price on
11-07-2026

$ 23.09 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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Oil Separator Hose - E46, Z4

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T#:579880

Part#: 55080

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Sale - Save 30% $ 24.99

This product was last offered at the strikethrough price on
11-07-2026

$ 17.49 USD

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$ 24.99

This product was last offered at the strikethrough price on
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$ 17.49 USD

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

Bav Auto Crankcase Ventilation Return Hose - E46 E39 E60 Z3

For vehicles with production date from 01/2000

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T#:638072

Part#: 11617504536

In Stock

Sale - Save 30% $ 26.99

This product was last offered at the strikethrough price on
11-07-2026

$ 18.89 USD

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This product was last offered at the strikethrough price on
11-07-2026

$ 18.89 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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Burgaflex Return Pipe - 11617504536 - E46, E39, E60, E83, E53 ...

For vehicles with production date up to 01/2000

T#:596611

Part#: 11617504536

In Stock

$ 17.99

This product was last offered at the strikethrough price on
09-26-2026

$ 13.99 USD

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$ 13.99 USD

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Keep your vehicle running crisp and leak-free with this premium return pipe manufactured by Burgaflex.

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

For vehicles with production date from 01/2000

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T#:640502

Part#: 11617504535

In Stock

Sale - Save 30% $ 24.99

This product was last offered at the strikethrough price on
11-07-2026

$ 17.49 USD

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$ 24.99

This product was last offered at the strikethrough price on
11-07-2026

$ 17.49 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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Burgaflex M52 M54 Crankcase Ventilation Hose (CCV) - 11157532649 - E4...

T#:596606

Part#: 11157532649

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$ 12.99 USD

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$ 12.99 USD

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Maintain peak engine health and precise air-fuel control by replacing your worn or cracked factory breather assembly with a premium Burgaflex replacement.

"Cold Climate" Crankcase Pressure Regulator Valve

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T#:35829339

Part#: 11617533400

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$ 69.99 USD

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$ 69.99 USD

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BMW vehicles are prone to oil separators freezing in cold weather if driven before the engine is fully warmed up. This can lead to a howling noise followed by multiple oil leaks. The crankcase breather valve vents oil vapor from the engine block to the valve cover, but condensation can sometimes cause it to freeze, leading to a failure of the entire oil separator system, causing it to crack and break down. To prevent damage to your engine, it’s best to replace all components of the oil separator system at once. Replacing everything ensures reliable performance and durability. Remember to also order a valve cover gasket to make the replacement process easier.

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Oil Separation & Breather System for BMW 3 Series E46 (1999-2005)

Sub-Categories

Bav Auto Crankcase Pressure Regulator Valve - BMW M52 M54

Oil Separator Hose - E46, Z4

Bav Auto Crankcase Ventilation Return Hose - E46 E39 E60 Z3

Burgaflex Return Pipe - 11617504536 - E46, E39, E60, E83, E53 ...

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

Burgaflex M52 M54 Crankcase Ventilation Hose (CCV) - 11157532649 - E4...

"Cold Climate" Crankcase Pressure Regulator Valve

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