How to Determine if a Car's Oil-Gas Separator is Faulty?
4 Answers
When a car's engine experiences shaking after cold starts, burning engine oil, or a rich mixture triggering the engine fault light, it can be determined that the car's oil-gas separator is faulty. Below are the main functions of the oil-gas separator: 1. The primary role of the oil-gas separator is to filter gases from the engine oil, maintaining its fluidity and lubrication effectiveness in optimal condition. The oil-gas separator effectively preserves the lubrication state of friction components in the engine, reducing wear and corrosion caused by insufficient lubrication. 2. Additionally, the oil-gas separator helps maintain the pressure in the crankcase equal to atmospheric pressure, minimizing oil leakage due to pressure differences. If a fault occurs, it should be addressed promptly.
I've been driving for half my life, and the main way to tell if a car's oil separator is failing is to watch for a few key signs. A noticeable increase in oil consumption, like having to top up every few hundred kilometers, is not normal. Blue smoke from the exhaust is a classic symptom because oil is getting into the combustion chamber; the engine shakes noticeably at idle and runs unevenly, feeling like it's about to stall. Also, the air filter might be coated with oil—just take it off and you'll see. If you suspect an issue, try checking the PCV valve's tube by pinching it to see if it's clogged or greasy. I always have the mechanic take a look at this thing during maintenance because once it fails, engine carbon buildup accelerates, fuel consumption spikes, and in severe cases, it can damage the engine's piston rings. Catching it early can save you from costly repairs.
I experienced a faulty oil separator just a few years after buying my car, and the symptoms were quite obvious when it failed. The engine oil level dropped rapidly, though there was no dashboard warning—I had to check it frequently. Upon starting, the engine noise became louder, almost like it was gasping for breath, and there was a foul oil smell from the exhaust pipe. I tried diagnosing it myself: first, I checked if the air filter was damp or had oil stains, which would confirm the issue. Then, I listened for any unusual rattling sounds at low engine speeds. The mechanic said it’s common in older cars or those with neglected maintenance, and replacing the part is simple and inexpensive. Over time, I also noticed slower acceleration—these are all warning signs that shouldn’t be ignored.
With years of experience in automotive repair, diagnosing a faulty oil separator is straightforward. Start the engine and listen for sounds; if there's abnormal noise in the valve area or rhythmic popping sounds, it may be due to incomplete oil separation. Monitor the engine oil consumption—a significant drop in a short period is suspicious. Check the exhaust pipe outlet; blue smoke is a typical sign. Excessive oil residue on the air filter after removal is direct evidence. This issue is common in high-mileage vehicles and can easily lead to carbon buildup. It's advisable to have the PCV system tested during regular maintenance.
