How Does an Oil Breather Work

What Does An Oil Breather Do? Oil breathers are installed on nearly every reciprocating engine

What is the purpose of an oil breather?

An oil breather system allows this build up of pressure to escape. If this pressure is allowed to build up and is not vented efficiently it can result in oil leaks from around the gaskets, crank seals, dipstick tube, and any other engine oil seal as the oil is effectively blown out by the increased crankcase pressure.

Why is oil coming out of breather tube?

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.