Texas summer is the only honest stress test for car A/C. Here's what fails, what costs what, and why 'just add refrigerant' usually means you'll pay for it twice.
The compressor squeezes refrigerant from gas to high-pressure liquid. The condenser (in front of your radiator) dumps the heat. The expansion valve drops the pressure, turning it back to a cold gas. The evaporator (under your dash) absorbs cabin heat. Anything in that loop fails: no cold air. Texas summer pushes the whole loop to its limits — that's why you find out in July.
At highway speed, air flowing through the condenser pulls heat away even with a weak fan. In traffic, the condenser fan has to do all the work alone. If the fan is dying, the condenser overheats, refrigerant high-pressure rises, the system protects itself by cycling off. That's why the warm-in-traffic complaint is almost always a tired fan or a dirty condenser, not 'low on freon.'
Cars built before 2015 use R-134a. Cars built after 2017 typically use R-1234yf (mandated for environmental reasons). 2015 and 2016 are mixed — depends on the model. R-1234yf is more expensive and needs different equipment. We have both. A shop without R-1234yf service capability will quietly refuse newer cars or guess.
If your A/C is low on refrigerant, refrigerant escaped somewhere — it doesn't just evaporate. Recharging without finding the leak means you pay for refrigerant now AND again in three months. A/C diagnostic with UV-dye leak detection is $129 and applies toward the repair; finding the leak first usually saves you the second recharge. We tell you the leak source before we recharge.
Four checks that narrow the problem before you spend on a diagnostic.
Turn the A/C to MAX and listen at the engine bay. The compressor clutch should click engage within 2 seconds. No click = electrical or low-pressure switch.
With A/C on at idle, the radiator/condenser fan should spin within 30 seconds. Not spinning = fan failure, fuse, or relay.
With A/C on MAX recirc, hold a thermometer (or your hand) at the center vent for 60 seconds. Below 45°F = healthy. 50-65°F = needs charge or has weak airflow. Above 65°F = compressor or major leak.
Park in a clean spot for 20 minutes with A/C on then off. A puddle of clear water under the passenger side is condensation drain — that's fine. An oily film is a refrigerant leak.
Call us or book online. Most appointments confirm instantly.