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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 (4)

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Bremmen "Cold Climate" Crankcase Pressure Regulator Valve Kit - BMW M...

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T#:2528129

Part#: 11617533400S1

In Stock

Sale - Save 30% $ 112.99

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

$ 79.09 USD

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Sale - Save 30%

$ 112.99

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

$ 79.09 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 all the components of the oil separator system together 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. Don't forget to order a valve cover gasket, throttle body gasket, and a new intake boot to make your separator change easier and more comprehensive.

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Crankcase Vent Hose

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T#:30629661

Part#: 11157831311

In Stock

Sale - Save 30% $ 31.99

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

$ 22.39 USD

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Sale - Save 30%

$ 31.99

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

$ 22.39 USD

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Engine Oil Separator Package - Level 2 - E46 325, E39 525i M54 ...

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T#:24344785

Part#: M54OILSEPKT

In Stock

Sale - Save 35% $ 177.99

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

$ 115.41 USD

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Sale - Save 35%

$ 177.99

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

$ 115.41 USD

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If you need to perform a complete oil separator system service, this Level 2 kit provides you with all of the main components necessary to service your engine oil separator system. This Level 2 kit includes the following: Oil Separator Hose from oil separator to dipstick tube Hose from oil separator to valve cover Hose from intake manifold back to the connector hose Hose from oil separator up to the intake manifold Throttle body gasket Throttle body inlet boot ICV rubber grommet Oil dipstick tube o-ring seal It is highly recommended to replace the oil dipstick tube with the updated design by BMW as this also a common place for sludge to build up.

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Bremmen Crankcase Ventilation Hose - E39 E53 E60 E83 E46

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T#:640147

Part#: 11611432559

In Stock

Sale - Save 30% $ 23.99

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

$ 16.79 USD

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Sale - Save 30%

$ 23.99

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

$ 16.79 USD

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Crankcase Vent Hose - From Valve Cover to Oil Separator - Fit BMWs with the M52 or M54 6 cylinder engine

Oil Separator Kit - Level 1

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T#:15710823

Part#: E46M5411_61KT

In Stock

Sale - Save 40% $ 124.99

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

$ 74.97 USD

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Sale - Save 40%

$ 124.99

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

$ 74.97 USD

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Replace all the components of the oil separator system together 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. 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. ur Level 1 kit includes the following; Oil separator Hose from oil separator to dipstick tube Hose from oil separator to valve cover Hose from intake manifold back to the connector hose Hose from oil separator up to the intake manifold

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Crankcase Ventilation Hose

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T#:30629689

Part#: 11157532649

In Stock

Sale - Save 30% $ 15.99

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

$ 11.19 USD

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Sale - Save 30%

$ 15.99

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

$ 11.19 USD

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Cold Climate Oil Separator Kit - Level 2

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T#:15744065

Part#: 114317400450-KT

In Stock

Sale - Save 44% $ 231.99

This product was last offered at the strikethrough price on
06-15-2026

$ 128.81 USD

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Sale - Save 44%

$ 231.99

This product was last offered at the strikethrough price on
06-15-2026

$ 128.81 USD

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If you are ready to perform a truly complete oil separator system service, our Level 2 kit provides you with all of our Level 1 kit components plus a throttle body gasket, throttle body inlet boot, ICV grommet, and dipstick tube o-ring. Our Level 2 Cold Climate kit includes the following: Oil separator - BMW cold climate recommended Hose from oil separator to dipstick tube - BMW cold climate recommended Hose from oil separator to valve cover Hose from intake manifold back to the connector hose Hose from oil separator up to the intake manifold Throttle body gasket Throttle body inlet boot ICV rubber grommet Oil dipstick tube o-ring seal It is highly recommended to replace the oil dipstick tube with the updated design by BMW as this also a common place for sludge to build up.

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"Cold Climate" Crankcase Pressure Regulator Valve

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T#:35829339

Part#: 11617533400

Back Ordered

$ 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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