Rough Idling Problems? The Importance of Crankcase Ventilation Explained

In order to ensure an engine is breathing properly, intake systems that are working at their best are essential. This includes several car parts, including the manifold and an air filter. Proper crankcase breathing, however, is just as important. Even if an engine is new, combustion pressure has to pass through the piston rings. In the event of a restriction or blockage, pressure will build up in the crankcase, which can result in several issues.

 

• The fuel and air mixture will be affected, resulting in rough idling and problems starting
• The oil will become contaminated by build-ups of acids and water vapours (the results of combustion), resulting in a prematurely worn engine and oil sludge
• Mixtures of oil and air will exit the car in the most convenient way possible, like the dip stick or the oil seals
• The car will consume more oil as the oil control rings lose their efficiency
• You’ll experience power loss because of a fuel charge that has lost its strength and will have to adjust the ignition to compensate for it

 

When you’re operating your Vauxhall, making sure there is proper crankshaft ventilation is essential. Here’s how everything works.

 

Positive Crankshaft Ventilation

Before 1963, car engines released oil deposits and vapours into the air and on the road. We didn’t think about how this affected the environment because there were no studies pointing out our wrongdoings. After this time, however, environmental pressures forced car manufacturers to change their tune. They developed Positive Crankshaft Ventilation, or PCV, in order to draw vapours into the crankcase. This meant the vapours could be taken into the car’s manifold and would be burned up before reaching the air.

A PCV valve is used to ensure all of these Vauxhall parts work together in unison and there is not upsetting of the air and fuel mixture. The valve regulates the exit of the vapours and gases. The faster the engine speed, the most vapours and gases it has to control. Because the vacuum in the manifold runs higher when engine speed is low, a PCV plunger is used to keep the crankcase from ventilating too much when you’re idling. This keeps the fuel and air mixture at the right levels. When you begin drive faster, like on the motorway, the manifold vacuum drops lower so there isn’t as much pressure on the PCV  plunger. This means more vapours can escape from the crankcase. Because there is more demand for fuel and air when the engine reaches higher speeds, the higher amount of vapours entering the combustion chambers at this speed don’t change the performance of your car.

 

A flame trap is also part of this PCV valve. If your car were to backfire, the manifold would force the PCV plunger to move to a position that closes off all escape for the vapours, fuel and air. This is important, as it prevents explosions from occurs within the crankcase.

When PCV systems were first developed, they were known as ‘open’ systems. These systems let vapours escape into the air still through the filler cap. As time went on, new developments were made and closed systems were created. With these systems, the filler caps aren’t vented. Instead, the air filter recirculates the air. These closed systems are much better for the environment and are the norm now. However, like any car parts, they must be maintained properly because they will break down over time. Most manufacturers want you to replace this valve every time you service your car.

 

Crankcase Ventilation and High-Performance Engines

In most cases, your PCV system should be able to handle the power your engine produces and control emissions so the environment is protected. However, even when you own a relatively new Vauxhall, you need to make sure all of the Vauxhall parts within and without the crankcases, including hoses and valves, are working properly and are replaced when necessary. Keep in mind that if you make alterations to the engine to increase its performance, you may upset readings from the sensor. This means that if you are making alterations for motorsport applications, you will need to provide for more ventilation as a result. If you don’t, you can put too much demand on the crankcase, and it may not be able to keep up. Before you purchase any other car parts to adjust this ventilation, however, there are some things to keep in mind. Never overfill wet sump engines. If the rods and crank plunge into oil each time they move, this will result in power loss, increased drag and more oil spray. As a result, you’ll lose more oil more quickly, which can cause problems with a number of Vauxhall parts, like the spark plugs and control rings for the oil.

 

Myths About the PCV Valve

When it comes to cars and car parts, myths and stories can be found everywhere. Unfortunately, not all of them are true. Here are some facts about PCV valves you shouldn’t ignore.

 

• Just because they rattle when shaken doesn’t mean the spring is metering as it should.

 

• PCV valves should never be cleaned and put back into the crankcase. There are some contaminants that stay on the valve no matter how well they are cleaned. In addition, the wear experienced by the spring will remain even after cleaning. These Vauxhall parts should always be replaced.

 

• PCV valves don’t last forever. They become worn and contaminated over time and must be replaced.

 

Symptoms of a Bad PCV Valve

Whether you’re looking directly at the crankcase or just noticing some changes in your Vauxhall, there are several signs that your PCV valve is going bad.

 

• A cloudy film on the outside of the valve or hose

 

• Water in the PCV valve or moisture build-up after short drives

 

• Oil leaks

 

• Noises, like whistles, whines or moans

 

• Check engine light with diagnostic codes for lean conditions in the engine

 

A properly breathing engine and crankcase are important to how your Vauxhall operates. Make sure you’re doing what you can to keep your PVC system and valve functioning efficiently by changing the valve at every major service time and watching for symptoms that the valve or ventilation are failing.