So, crankcase emission control, is only one part, of the emission control system.

Consequently, it deals with the, terrible “blow-by” gases, accumulated in the engines crankcase.

Basically, the system works by, removing terrible gases, from the crankcase. Then, it sends them back through the intake, so that they can be, burned for a second time.

Actually, crankcase emission control, has been around for ever and works, very well at doing its job.

So, the system usually consists of a tube, a one-way (PCV) valve and a vacuum source. (such as, the intake manifold). Consequently, this hole system, is more commonly know as, the positive crankcase ventilation (PCV) system.

Above all, if we did not have this system, we would have to deal with:

  • Oil vapor in the crankcase
  • Engine sludge
  • Oil diluted with unburnt fuel

Terrible “blow-by” gases, cause, three terrible problems:

  1. Firstly, by destroying the lubricating properties of the engine oil.
  2. Secondly, it allows the formation of engine sludge and varnish.
  3. Finally, it forms, corrosive acids, which damage engine parts.

So, a failed (PCV) valve or related crankcase emission control component, can produce a number of symptoms. For example, if the valve gets stuck, in the closed position. Then, you’ll notice one or more of these symptoms:

  • Increase in internal engine pressure.
  • Failure of one or more oil seals or gaskets.
  • Engine oil leaks.
  • Moisture and sludge buildup inside the engine.
  • Engine surges and possibly black smoke.

But, if the (PCV) valve gets stuck, in the open position. And, a crankcase emission control system hose, gets disconnected or ruptured, producing a vacuum leak. Then, you’ll notice one or more of these symptoms:

  • Engine misfires at idle.
  • Lean air-fuel mixture.
  • Presence of engine oil in (PCV) valve or hose.
  • Increased oil consumption.
  • Hard engine start.
  • Rough engine idle.

In addition, a (PCV) valve stuck open, can trigger the “check engine” light, due to increased air flow.


Choose Your  Crankcase Emission Control Help Topic Below

Engine Oil Consumption, Is On The Rise, Where It Go’s And Why


PCV Valve – How Does It Work – Failure Signs – Ways To Test The System

The (PCV) System – One Of The Biggest Causes Of Engine Oil Sludge

PCV Valve (Positive Crankcase Ventilation System)

(PCV) Valve – Regular Maintenance – Why You Need It

Positive Crankcase Ventilation System- What Does It Do

Engine Sludge – Top 2 Ways To Stop Or Slow Down Engine Sludge


Thank You !