What Causes Oil in the Car Throttle Body?
2 Answers
Car throttle body has oil because the engine's exhaust gas is recirculated into the intake manifold. The throttle body is a crucial component of the fuel-injected engine system. Its upper part connects to the air filter, and the lower part connects to the engine block, serving as the throat of the car engine. Failing to clean the throttle body for an extended period can cause errors in the throttle opening and allow air with impurities to enter the engine combustion chamber, leading to abnormal engine operation. Traditional throttle bodies directly link the throttle pedal to the throttle opening via a cable or linkage, controlling the air intake and fuel injection. In contrast, electronic throttle bodies consist of the engine, speed sensor, and throttle, using an electronic throttle control system to precisely regulate the throttle opening.
I've been repairing cars for almost twenty years, and I've seen quite a few cases of oil in the throttle body. The most common issue is a problem with the PCV system. That valve is used to recycle oil vapor, and if it gets clogged or leaks, oil can easily backflow into the throttle body. When the air filter is too dirty or not properly sealed, oil can also get in. Another possibility is aging seals, like the gasket near the intake valve wearing out over time, causing oil to leak onto the throttle body surface. If you notice this, don't take it lightly. If not addressed promptly, it can lead to severe carbon buildup, rough engine operation, a spike in fuel consumption, and noticeably sluggish acceleration. It's best to check the PCV valve and air filter during regular maintenance. Using a specialized cleaner to spray it can help, but in severe cases, replacing the parts is the safest option.
