Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Piston Engine Models: Gasoline
The PCV system includes 2 hoses and a PCV valve. Crankcase vapors are normally drawn from valve cover through PCV valve and into intake manifold. A hose from the air cleaner to the valve cover supplies fresh air to the crankcase.
When intake manifold vacuum drops due to heavy loads, the amount of blow-by exceeds the capacity of the PCV valve. Air then flows directly from the valve cover into the air cleaner and carburetor. When engine is not running, the PCV valve is closed and vapors are stored in the crankcase.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.