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Q: heater not hot.

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The blend door is fine and there is good flow as far as we can tell. We circulated air through each line with the engine intake clamped off and fluid flowed. Still no heat. You can see the heater coil lines swell a little with pressure but they do not get hot.
My car has an automatic transmission.

A: Hi there. Assuming, the temperature blend d...

Hi there. Assuming, the temperature blend door is properly functioning, would lead me to believe the heater core is restricted or air is trapped and a cooling system flush could resolve the issue. The heater control valve and/or vacuum control to the valve may be at fault. Proper diagnoses should be performed to avoid unnecessary repairs. I recommend having your vehicle’s heater is not hot be diagnosed and repaired by a certified technician, such as one from YourMechanic.

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