PCV, EGR, and Oil Separator Membrane Repair Kits for Reliable Crankcase Ventilation
If your BMW hisses at idle or you find oil in the intake, a targeted PCV diaphragm repair kit or a membrane valve cover replacement is often the fastest way to fix the root cause. Klifex focuses on BMW fitments such as M52, M54, N52, N54, N47, N57, B47 and B57, and we also supply membrane kits for VW, Audi, Porsche, Volvo, Land Rover where needed.
What the PCV / EGR System Does
Start with the simple idea: the PCV system keeps the engine at the right internal pressure. It takes blow-by gases and oil vapor out of the crankcase and routes them back into the intake. The PCV valve, diaphragms, and oil separator membranes control flow and trap oil mist. When a membrane or valve fails, the unit either leaks vacuum or overpressurizes the crankcase. Both situations cause rough idle, oil in the intake, and diagnostic codes.
On turbo cars, failed parts speed up DPF loading and sensor fouling, so sealing and separation matter more than they look. Turbos, intercoolers, and DPFs hate oil contamination very much. Replacing a simple membrane or valve often prevents much larger jobs and money loss in the future.
When You Need a PCV or Crankcase Breather Repair Kit
Choose a PCV diaphragm repair kit or PCV hose kit when the diaphragm is torn or a breather hose is visibly cracked. Order a membrane valve cover replacement for BMW M52, M54, and B47 families when inspection shows a damaged membrane or separator. Pick a full crankcase ventilation kit or crankcase breather kit when multiple seals leak or the separator housing is damaged.
Here are the clear signs that the ventilation system needs attention:
- Rough idle, stalling, or unstable RPM.
- Whistling or hissing from the valve cover or breather hoses.
- Excessive oil consumption or oil in the intake or intercooler.
- Visible oil leaks from valve cover gaskets or separator housings.
- Vacuum leak symptoms and lean codes on the scan tool.
If you see one or two of these, inspect the diaphragm and hoses. If multiple signs appear, plan a kit replacement plus intake cleaning.
Note! Consider a PCV bypass kit or PCV valve delete kit only for dedicated race or off-road use. If you are unsure which approach is right, start by isolating the failure: is it a single hose, the diaphragm, or the separator housing? A targeted repair kit is usually faster and cheaper, but when several items are aged, a full kit prevents repeat work.
Benefits of Using a PCV Diaphragm or Breather Kit
A proper kit brings practical gains:
- Restores correct crankcase pressure and steadies idle.
- Stops vacuum leaks and the hissing that signals a torn membrane.
- Reduces oil consumption and keeps oil out of the intake.
- Costs less than replacing a whole valve cover, and fits by engine code.
- Helps turbo engines remain reliable under boost.
Beyond the immediate fix, using an engineered repair kit improves long-term reliability. New elastomers and correctly sized O-rings reduce the chance of recurring leaks and prevent oil vapor from degrading sensors and DPF systems. For DIYers, a well-packaged BMW kit makes installation straightforward and repeatable
Types of PCV and Breather Repair Kits
PCV diaphragm repair kits, such as PCV membrane BMW E39/E38 and valve cover membrane BMW B47/B57, replace the membrane, spring, and seals. Crankcase breather kits include reinforced hoses, check valves, and fittings for reroutes or replacements. PCV hose kits and elbow kits replace brittle factory tubing.
Oil separator membrane kits and EGR diaphragm replacements restore separation on BMW and European engines. Catch can and breather plate kits provide supplemental oil control on high blow-by applications.
What’s Included in PCV and Membrane Repair Kits
Kits typically include oil-resistant diaphragms, springs, O-rings, gaskets, reinforced hoses or elbows, and small mounting hardware. Klifex often uses upgraded elastomers for high-temperature and oil resistance. Parts are produced to fit specific engine codes, so installation is straightforward and repeatable.
Why Choose Klifex Membrane and PCV Repair Kits
Klifex focuses on BMW-matched kits with clear engine-code fitment, upgraded materials, and precise tolerances. That reduces callbacks and speeds repairs for shops and DIYers. Order by engine code or VIN to get the exact PCV repair kit, PCV diaphragm repair kit, or membrane valve cover your car needs.
Frequently Asked Questions
- Is it safe to drive with a failed PCV?
Short trips are OK, but prolonged driving risks sensor fouling and increased oil use.
- Do I need a catch can?
For turbo engines with heavy blow-by, a catch can is a useful supplement.
Need help choosing the right PCV kit or membrane for BMW? Send your VIN code and we will recommend the correct kit and any intake cleaning your tech should plan.
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