A Guide to the Engine Crankcase Breather Hose for the 2011-2016 BMW 535i
Understand why this critical plastic hose on your N55 engine fails and how to choose the right replacement.
- The plastic breather hose on the N55 engine is a common failure item due to heat and age, causing vacuum leaks.
- Symptoms include a loud whistling noise, rough idle, and a Check Engine Light with lean codes.
- Replacement is simple and highly recommended for any DIY-capable owner to prevent further issues.
- Choosing a quality aftermarket brand like CRP/Rein offers OEM quality without the dealer price tag.
Why This Hose Fails on the BMW 535i
The engine crankcase breather hose on the 2011-2016 BMW 535i is a known failure point. The original part is made of hard plastic that sits on top of a hot engine. Over many heat cycles, this plastic becomes extremely brittle. Eventually, it will crack or break, sometimes with just a slight touch during other maintenance. This failure creates a vacuum leak, which can cause a range of engine problems.
Symptoms of a Bad Breather Hose
When the breather hose fails, your car will let you know. You may experience one or more of these symptoms:
- Whistling or Sucking Noise: A high-pitched whistle or sucking sound from the engine bay 🎬 Watch this video to hear and diagnose the PCV squeal. at idle is a classic sign. This is unmetered air being sucked through the crack in the hose.
- Rough Idle: The engine may run rough, idle poorly, or even stall. This is due to the vacuum leak disrupting the air-fuel mixture.
- Check Engine Light: A vacuum leak will often trigger a Check Engine Light. You might see codes related to a lean air-fuel mixture or engine misfires.
- Increased Oil Consumption: Improper crankcase ventilation can lead to higher than normal oil consumption.
Is there a recall for this part?
While there have been extensive recalls (NHTSA recalls 17V-683, 22V-119) for the PCV valve *heater* on many BMWs, including some 5-series models, these recalls do not cover the hose itself breaking from age. The recalls address a fire risk from the heater element short-circuiting, not the physical failure of the plastic hose.
Choosing the Right Aftermarket Part
When replacing this hose, you have options. The Genuine BMW part is available, but high-quality aftermarket parts can offer the same performance for less money.
OEM vs. Aftermarket Quality:
The original BMW hose is the part that becomes brittle and fails. An aftermarket part from a reputable OEM supplier can be a smart choice. These are often the exact same parts that were installed at the factory, just without the BMW logo and price tag. Some owners even prefer upgraded silicone hoses for better long-term durability against heat.
Brand Tiers for Your BMW 535i:
- CRP (Rein): CRP is a well-regarded brand that is an Original Equipment Manufacturer (OEM) for BMW on many parts. Choosing a Rein-branded hose often means you are getting a part that meets or exceeds the original specifications, providing a great balance of quality and value.
- Gates: Gates is a globally recognized leader in automotive hoses and belts. While generally a trusted brand, for specific molded BMW hoses, some forum users prefer to stick with OEM or a known OEM supplier like Rein to ensure perfect fitment.
- Vaico: Vaico is typically positioned as a budget-friendly option. For a critical component like a PCV hose on a turbocharged engine, it is often recommended to invest in a higher-tier brand like CRP/Rein or Genuine BMW to ensure longevity and avoid premature failures.
Pro Tip: During replacement, be extremely careful with the plastic connectors on both the valve cover and the intake pipe. They also become 🎬 See this clever trick for removing the hose without breaking connectors. brittle with age and can break easily. The replacement is straightforward and can be done with basic tools.
🎬 Follow this step-by-step walkthrough to replace the hose yourself.| Part Type | Estimated Cost |
|---|---|
| New Aftermarket (CRP, Gates) | $55.46 - $95.99 |
| New OEM (Genuine BMW) | $45 - $65 |
| Shop Labor | $120 - $200 |
Frequently Asked Questions
Why does this hose fail so often on the BMW 535i?
The hose is made of a rigid plastic that is constantly exposed to high temperatures from the engine. This heat cycling causes the plastic to lose its flexibility and become brittle, leading to cracks and breaks.
Can I just tape the broken hose?
Taping a broken hose is a temporary fix at best, just to get you home. The engine's vacuum and pressure will quickly defeat the tape, and the problem will return. Proper replacement is the only long-term solution.
What happens if I don't replace a broken breather hose?
Ignoring a broken breather hose can lead to more significant problems. A persistent vacuum leak can cause rough running, foul spark plugs, and damage catalytic converters. Incorrect crankcase pressure can also stress engine seals, leading to expensive oil leaks.
Is an aftermarket breather hose as good as the original BMW part?
Yes, a high-quality aftermarket hose from an OEM supplier like CRP/Rein can be just as good, if not better, than the original part. Since the original design is prone to failure, some aftermarket solutions even use improved materials like silicone for greater durability.
Helpful Videos
Technical Specifications
OEM Part Numbers: 11127584128
This hose connects the valve cover to the fresh air intake pipe. It is made of rigid plastic and includes an electrical connector for the built-in heater element.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- BMW 535i: