Do you need a breather on your valve covers?
Yes you do need something to vent the crankcase pressure or you’ll start noticing stuff like blown out intake end seals, leaky rear main seal, dipstick blown out of the tube, etc… A hi-performance engine has more crankcase pressure so more “breather” is needed.
What does the valve cover breather do?
The thought behind the breather is that you are supposed to get more fresh air flow down into the crankcase from the valve cover. This increases the cycle of oil vapor flow out of the crankcase. The added fresh air displaces the oil vapors in the crankcase with the assistance from the IM vacuum sucking it out.
What is a valve cover breather hose?
The hose serves the same purpose as the pcv system on a car, which is to allow the crankcase to vent rather than build up pressure. Cars have a pcv valve that allows the crankcase to vent (hence the name – positive crankcase ventilation), but not draw air.
Can I use a breather instead of a PCV valve?
Registered. Put me in the PCV camp. A PCV system actually clears combustion gas blowby from the engine, whereas breathers will only allow positive pressure to escape. These gases will combine with moisture in the air and oil to create acids and sludge.
Why is oil coming out of my breather pipe?
Pressure leakage from worn seals causes the oil to be forced down into the inlet passage and back through to the inlet filter. Typically you will get an excess of oil being blown out through the crankcase breather too as the cylinder head/rocker cover is pressurised blowing back down to the crankcase.
Why does oil come out of valve cover breather?
If the engine is producing blow-by gases faster than the PCV system can dispose of them, an increasing surplus becomes trapped in the crankcase, causing excess pressure and, inevitably, oil leaks. In addition, the low-level vacuum draws in fresh air to the crankcase from the crankcase breather.
What happens if you disconnect your PCV valve?
PCV system routes oil vapours back to the intake to prevent blowing them to the atmosphere. If you disconnect it you’ll have a cleaner air available to the combustion process, and so better performance.
What happens if you drive without a PCV valve?
A PCV valve attaches via a rubber hose to the intake manifold. If you remove the PCV valve there will be no place to attach the hose to the engine and there will be a massive intake leak. The intake leak will cause your engine to run rough or die all together.
