Back to all

Your Vehicle's Hissy Fit (AC System)

June 11, 2023

When you hear hissing sounds coming from your vehicle, you might start thinking the worst.   One type of hissing coming from around your air conditioner may be a normal sound, or it could be a sign of serious trouble.

First - the normal sound.  When you turn off your vehicle, the refrigerant goes from its high-pressure side to the low-pressure side. Some of those noises are normal.  But when it hisses all the time, that's another story.

One cause could be that the refrigerant is leaking.  Air conditioners are fairly complex systems that involve various pumps, hoses, valves and motors.  When your air conditioner is cooling, the refrigerant changes from a gas to a liquid and back.  That refrigerant is under pressure, and there are many places it can leak from. 

A hissing sound can also be a failed valve in your air conditioner's compressor.  It is what controls the refrigerant's pressurization.  It's important to have this fixed fairly quickly after it develops a problem because when it isn't, that can lead to more extensive—and expensive—repairs.

If you hear screeching coming from your air conditioner at the same time you hear hissing, your compressor may be on its last legs. It could also be a defective clutch. 

Any time you hear a noise you haven't routinely heard before, bring your vehicle to us so a technician can check the various components and properly repair the problems.  Air conditioning systems are complex and are best handled by a professional with the right tools and equipment.  When your AC has a hissy fit, let us cool it off and you at the same time.  

Tuffy Bloomington
1505 East Vernon Avenue
Bloomington, Illinois 61701
309.662.0537

More articles from Tuffy Bloomington

Go with the Flow (MAF Sensor Replacement)

October 27, 2025

If your vehicle has an internal combustion engine, it depends on two things to make propulsion power for you to be able to motor on down the road: fuel and air. The engine mixes the two in just the right proportion so that they can be ignited, creating a series of tiny explosions that are coordi... More

Losing Your Cool (AC Condenser Replacement)

October 23, 2025

Its always more comfortable in your vehicle when you can control temperature and humidity in the cabin. Air conditioning, which is standard on most newer vehicles, is a vital part of that comfort, and a key component of that system is the condenser. The condenser converts the refrigerant gas into... More

Knowledge is Power (Battery Testing)

October 12, 2025

Its likely happened to you once or twice. You head to your vehicle, open the door, turn the key and lo and behold, your battery is dead. Now youre stranded, may have to get a jump or a tow, and youll definitely be late for wherever you were headed. While your vehicle may sometimes give you warni... More