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.
6-Cylinder Engines
The thermal vacuum switch is a normally closed switch. When engine oil temperature is below 150°F, the TVS is closed allowing manifold vacuum to the actuator valve. Vacuum pulls the diaphragm in the actuator, closing the EFE valve. This causes the hot exhaust gases to be routed to the base of carburetor. When oil temperature is above 150°F, the thermal vacuum switch opens. This stops vacuum to the actuator. A spring in the actuator opens the EFE valve.
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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.