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
1978 Models
- After inspecting vacuum hoses, start and run cold engine at idle. Ensure that secondary EGR valve does not operate when engine speed is increased to 2500 RPM.
- If secondary valve operates, replace thermo valve. When coolant temperature exceeds 131°F (55°C), secondary valve should operate with engine at 2500 RPM. If valve does not operate, replace thermo valve.
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.
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