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.
Description & Operation
Components of system include a connecting vent hose between crankcase and oil tank, a main vent hose with orifice between the oil filler tube neck and air intake duct above throttle, an auxiliary vent between oil tank and intake port below throttle, vacuum control, air switching valve, and temperature switch.
Crankcase vapors and blow-by gases flow into oil tank, where excess oil is separated from gases. At temperatures above 50°F (10°C), gases are drawn into intake manifold through main vent system. At temperatures below 50°F (10°C), temperature switch opens allowing vacuum to open auxiliary vent passage in air, switching valve. Gases are then drawn into engine through auxiliary vent to prevent throttle icing.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.