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Why Your Car A/C Stops Cooling and What You Can Do About It in Mineral Wells Tx

  • Writer: Kasi Drummer
    Kasi Drummer
  • 4 days ago
  • 3 min read

When your car’s air conditioning starts acting up in this Texas heat, it’s more than just an inconvenience—it’s a mission-critical comfort issue. At S&S Auto and Diesel, we specialize in helping drivers across Mineral Wells, TX, stay cool with professional HVAC diagnostics and repair. If you're wondering whether you need an A/C recharge, a new compressor, or something in between, we’ve got answers.


Woman feeling her AC unit in her car

A/C Blows Warm at Idle but Cools While Driving. Why?

This is one of the most common complaints we hear. When your A/C works fine while you’re cruising but gets warm at red lights or in traffic, the likely culprit is low airflow across the condenser.


That could be caused by:

  • A failing radiator or condenser fan (or fan clutch if it's mechanical)

  • A dirty or blocked condenser

  • Low refrigerant levels


In many cases, it’s the fan clutch on older trucks that doesn’t fully engage at idle, meaning it doesn’t pull enough air over the condenser to shed the heat. On the flip side, if you’re overheating only on the highway, that could point more toward a restricted radiator or low coolant levels—not the fan. We test all of these.


Why does my A/C feel weak after a few minutes?

If your A/C starts out icy and then fades to warm or just "meh," this could mean:

  • The evaporator coil is icing over due to low refrigerant

  • A faulty expansion valve or pressure sensor

  • A bad blend door actuator, which fails to keep hot air separated from cold


When refrigerant is low, the pressure drop across the expansion valve can cause moisture to freeze on the evaporator coil. This blocks airflow until the ice melts, then it cools again—only to repeat the cycle. It can also be a sensor misreading pressures and cycling the compressor too early.


Do I need an A/C recharge or is it a leak/compressor/blend door?

Here’s how we figure that out:

  • Step 1: Check refrigerant pressure

    • If it’s low, we add UV dye and use a refrigerant sniffer to detect leaks. We’ll inspect the condenser, evaporator, fittings, and lines.

  • Step 2: Check system cycling

    • If the compressor kicks on and off too frequently or not at all, we may be looking at a sensor or electrical fault.

  • Step 3: Check airflow and blend doors

    • If it only blows on one side or the temperature can’t be adjusted, we inspect blend door actuators, a common issue on many late-model trucks and SUVs.


A recharge only helps if the system is sealed and healthy—topping off a leaking system is a short-term patch, not a fix.


Overheating on the highway but cools at idle..... Is it the fan clutch or thermostat?


If your vehicle is overheating at highway speeds but seems okay around town, you may have:

  • A partially clogged radiator

  • A restricted coolant flow path

  • Low coolant due to leaks or air pockets

  • A failing thermostat stuck partially closed


A fan clutch could cause overheating but typically that happens more in stop-and-go traffic, not at 70 mph. Highway overheating points more often to coolant flow or radiator issues.


Heater works but A/C doesn’t (or vice‑versa). Could this be your blend door/actuator?

Yes, absolutely. Blend doors control how air moves through the heater core and evaporator coil.

  • If the heater works but A/C doesn’t, a stuck door may be bypassing the cold coil.

  • If you get different temps on driver/passenger sides, that’s a strong indicator of an actuator or door failure.


These components are often tucked deep in the dash, but modern diagnostics can pinpoint failure before a single panel comes off.


Let Us Help You Stay Cool in Mineral Wells

At S&S Auto and Diesel, we know that HVAC issues can feel overwhelming. Our team will give you straight answers and explain exactly what's going on with your vehicle, no pressure and no upsells.


Rhonda, our owner, built this shop with the intention of creating a space where folks feel taken care of, especially women, who often feel overlooked in this industry. As a woman-owned business in Mineral Wells, we work hard to be the auto shop people trust and return to, season after season.


Stop by our shop at 205 NE 22nd Ave, Mineral Wells, TX, or give us a call at (940) 325-1221 to schedule your inspection.


Whether you need a recharge, diagnostics, or just a second opinion, we’re here to keep you and your family cool and comfortable all summer long.

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