Back to all

Your Vehicle's Hissy Fit (AC System)

February 4, 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 Tire & Auto Service Center Lockport
600 E 9th Street
Lockport, Illinois 60441
815-838-3700

More articles from Tuffy Lockport

Have a Ball! Know your Ball Joints (Ball Joints)

March 15, 2026

We all have joints in our own skeletal system, but did you know your vehicle has some joints of its own? One of the most important is called a ball joint. One of the interesting things is that it's somewhat similar to the ball and socket joints we have in our hips and shoulders. A ball joint all... More

Give me a Brake (Light)!

March 8, 2026

If that little brake warning light pops up on your dash, do you know what it means? Well, if you said no, you wouldn't be alone. You know it has something to do with your brakes, but exactly what? You're not sure. One of the reasons is that it could mean a lot of different things. It could be som... More

Command Performance (Engine Air Filter)

March 1, 2026

The internal combustion engine in your vehicle counts on two things that mix together to be burned in the engine for power: fuel and air. Both are important, of course. If you run out of fuel, your engine wont run at all. Since theres plenty of air around, you wont run out of air, but you coul... More