Symptoms of a Faulty or Faulty Vented Oil Separator

Common symptoms include smoke coming from the exhaust, the Check Engine light coming on, excessive oil consumption, and sludge under the oil cap.

Oil is the lifeline of any internal combustion engine. It is designed to properly lubricate virtually all internal engine components in your car, truck or SUV; and must do so consistently to reduce wear on engine parts. During normal operation, the oil inside your engine mixes with air, but it needs to be regenerated and redirected back to the oil pan while the air is separated and sent to the combustion chamber. This task is accomplished by using a vented oil separator in conjunction with other venting elements in and around the engine.

Whether your vehicle runs on gasoline, diesel, CNG or hybrid fuel, it will have an oil venting system installed. Different cars and trucks have unique names for this part, but when they fail, they show similar symptoms of a bad or faulty vented oil separator.

When a vented oil separator begins to wear out or fails completely, damage to engine internals can range from minor to total engine failure; you will recognize a few of these warning signs listed below.

1. Smoke from the exhaust pipe

The vented oil separator is designed to remove excess gases (air and other gases mixed with oil) from the oil before it enters the combustion chamber. When this part is worn out or past its expiration date, this process is ineffective. The introduction of additional gases into the combustion chamber hinders the clean combustion of the air-fuel mixture. As a result, more engine smoke will be emitted through the car's exhaust system. Excess engine smoke will be most noticeable when the vehicle is idling or accelerating.

If you notice white or light blue smoke coming out of the exhaust, you should see a certified mechanic as soon as possible so they can diagnose and replace the breather oil separator. Failure to do so quickly can result in damage to cylinder walls, piston rings and cylinder head components.

2. The Check Engine light is on.

When oil and gases begin to burn, the temperature inside the combustion chamber usually rises. This can, and often does, trigger a warning inside your vehicle's ECU and then send a warning to the dashboard by flashing the Check Engine light. This warning generates a warning code that is downloaded by a professional mechanic using a scan tool connected to the vehicle's computer. If you notice the Check Engine light on your dashboard, it's a good idea to head home as soon as possible and contact an ASE certified mechanic as soon as possible.

3. Excessive oil consumption

Another common sign of a damaged or worn vent oil separator is that the engine is consuming more oil than it should. This problem is common with engines over 100,000 miles and is often considered typical wear on internal engine components. However, many professional mechanics agree that the main reason for the extra oil consumption is that the vented oil separator does not do what it was designed to do. If you notice the "Check Oil" light comes on, or when you check the engine oil level, it is often low and you need to add oil frequently, have a professional mechanic inspect your vehicle for a damaged breather oil separator.

4. Dirt under the oil cap

A bad or defective vented oil separator will also not be able to remove condensate from the oil. In many cases, excess moisture accumulates under the filler cap and mixes with dirt and debris trapped inside the engine. This creates sludge or oil combined with dirt that appears under or around the oil cap. If you notice this problem, have a certified mechanic inspect and diagnose the problem with your vehicle.

In an ideal world, our engines would run forever. Believe it or not, if you do regular maintenance and service, there should be no problems with the vented oil separator. However, such a condition is quite possible even with proper maintenance. If you notice any of the above warning signs of a bad or malfunctioning vent oil separator, don't hesitate - contact a certified mechanic as soon as possible.