Oil Separation & Breather System for BMW 5 Series E39 (1996-2003)

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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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Upgraded Silicone CCV Hose (11151703775) - M52/S52
For Vehicles with a Production Date up to 09/1998
Turner Motorsport - Corporate Logo
T#:46203574
Part#: 059015LA02
Ships on Aug 17, 2026
Sale - Save 49% $ 59.99

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03-03-2026

$ 30.74 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 M52/S52 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 M52 or S52 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 cyclone separator to the valve cover. It replaces OEM part number 11151703775.

Features:

Silicone construction ensures a durable replacement that is sure to outlast OE plastic Designed as a direct replacement for the factory breather hose - not too short like many aftermarket alternatives, and does not require cutting to fit Works seamlessly with the OEM OBDII valve cover and cyclone separator, as well as the Turner Motorsport Billet Aluminum Valve Cover (T#26238386) Design:

Three-ply wire-reinforced fluorosilicone hose is designed to resist degradation due to exposure to oil vapors O-rings are pre-installed in OE Norma connectors for a lasting seal Includes pre-installed 430 stainless steel 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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Bav Auto Crankcase Pressure Regulator Valve - BMW M52 M54
For vehicles with production date from 09/1998
Bavarian Autosport - Corporate Logo
T#:640207
Part#: 11617501566
In Stock
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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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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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
Bavarian Autosport - Corporate Logo
T#:638072
Part#: 11617504536
In Stock
Sale - Save 20% $ 26.99

This product was last offered at the strikethrough price on
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$ 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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Bavarian Autosport - Corporate Logo
T#:579869
Part#: 54546
Ships on Aug 11, 2026
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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$ 26.99

This product was last offered at the strikethrough price on
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ECS - Corporate Logo
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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Bavarian Autosport - Corporate Logo
T#:640206
Part#: 11617501563
In Stock
Sale - Save 20% $ 47.99

This product was last offered at the strikethrough price on
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$ 38.39 USD
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This product was last offered at the strikethrough price on
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$ 38.39 USD
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An integral part of the emissions system, the PCV valve lets the crankcase breathe. This allows proper intake and exhaust flow, resulting in proper running and operation. When the crankcase vent valve fails it can cause excessive oil consumption, engine fault codes, and poor idle. 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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Bavarian Autosport - Corporate Logo
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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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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Bavarian Autosport - Corporate Logo
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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Cold climate version for extra insulation! Fits all E46 and Z4 chassis equipped with an M54 engine.

ECS - Corporate Logo
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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Sale - Save 11%
$ 10.99

This product was last offered at the strikethrough price on
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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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