Back to all

Your Vehicle's Hissy Fit (AC System)

October 20, 2024

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 Chicago (Diversey Pkwy)
1400 West Diversey Pkwy
Chicago, Illinois 60614
773-929-3622

More articles from Tuffy Chicago

It's (Not) Complicated (Engine Air Filter)

November 2, 2025

While many components of your vehicle are complex and composed of lots of mechanical and electrical parts, there's one that isn't complicated but still important. It's your engine air filter. (And, we should point out, the engine air filter isn't to be confused with the cabin air filter. The ca... More

Don?t Be Hosed (Radiator Hose Replacement)

October 27, 2025

If you are like most drivers, you dont worry too much about what shape your radiator hoses are in. But they are a vital part of your coolant system, helping carry engine coolant from the hot engine to where it is cooled off in the radiator. When the cooling system has a problem, you will likel... More

Keeping Your Cool (Coolant System)

October 23, 2025

No matter what the weather is like outside, your internal combustion engine expects to keep its cool all the time, even when it's really cold. That's because engines create the power that moves you to your destination by a series of tiny explosions of a fuel and air mixture. In turn, that genera... More