
Replace Your Car's AC Thermal Expansion Valve or Orifice Tube
Your car or truck's AC system is under extreme pressure and the thermal expansion valve or orifice tube monitors the amount of pressure and the temperature of your A/C system. It calculates the precise amount of refrigerant that can safely go into the evaporator. A failing expansion valve or orifice tube often causes a vehicle's air conditioner to blow hot air.
Replace or Repair
- Expansion Valves: Too much refrigerant causes your evaporator to get too cold whereas too little refrigerant would result in inadequate cooling. The expansion valve is a complex valve that regulates refrigerant flow. This process of metering the refrigerant adjusts the flow according to the temperature of the refrigerant in the evaporator coil. Talk to one of the pro mechanics at Protrans Automotive & Transmission Specialists, as this part can be replaced on its own and does not require the entire replacement of the AC assembly.
- Orifice Tubes: Unlike the expansion valve, the orifice tube is a simple fixed device with no moving parts. It therefore cannot vary the flow of refrigerant into the evaporator, but rather causes a permanent restriction in the system. However, like the expansion valve the orifice tube regulates refrigerant flow through the system and filters debris which may come through in its screen. Often fixing a "bad orifice tube" requires replacing the entire evaporator assembly.

OUR REVIEWS


Randy Bednorz, 07/24/2025A 2025 UPDATE TO MY PROTRANS REVIEW My orphaned ISUZU SUV is now more than 30 years old. Neither the engine (208,000 odo miles) nor the transmission (70,000 odo miles) show any indication of wear, oil consumption or degraded performance. Last year, we upgraded all the engine sensors and the HO2 sensor on the cat converter. This cost me some ducats, but the vehicle runs like brand new, starts the minute you twist the key -- cold, warm or hot. Gas consumption is still factory spec. We've recently replaced the front wheel bearings and rebuilt the steering gear-box. ProTrans has continued to give me stellar support and advice. They've been worth every penny so far. If something goes wrong during the process of a repair, they'll correct it without further charge. I've been thinking to buy a new or pre-owned/lo-miles ride for several years now, and I've been ready to execute my plan for a Toyota hybrid. I just don't have to do it this year. So I'm putting it off. Again. =======================================