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.
1978 Plymouth Arrow Base, Automatic TransFACTORY OEM SERVICE PROCEDURE
1976-77 Models
- Remove thermo valve and allow it to cool to room temperature. Check valve by blowing into vacuum fittings. Valve is normal if EGR fitting allows air to pass freely and distributor fitting is blocked.
- Immerse thermo sensor in 140°F (60°C) water, for at least one minute. Valve is normal if no air flows through either fitting. Immerse thermo sensor in boiling water for at least one minute. Valve is normal if EGR fitting blocks air and distributor fitting allows air to flow freely.
Factory Service Tools
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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.