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.
THERMACTOR Air Control
This system is similar to the standard Thermactor air pump system, but it also adds a second air control valve (in addition to the by-pass valve), and a second exhaust check valve. Other system components include the air pump, Ported Vacuum Switch (PVS) and the Temperature Vacuum Switch (TVS).
Above 125°F coolant temperature, air pump air is routed to the mixing chamber of the dual catalytic converter. Below 125°F coolant temperature, the PVS applies vacuum to the air control valve which directs air pump air to the exhaust manifold to decrease HC and CO during warmup.
A catalyst protection feature is used when the TVS (on the air cleaner) senses inlet air temperatures below 49°F. This causes the by-pass valve to dump air pump air to the atmosphere (not to the exhaust manifold or converter mixing chamber).
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.