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

Making Sense of the O2 Sensor (Oxygen Sensor Replacement)

April 13, 2025

As you know, todays vehicles rely on a lot of computers in them to keep them running clean and efficiently. Those computers depend on information delivered by several sensors throughout the engine and exhaust system. And one of the most important is the oxygen sensor. Known as the O2 sensor f... More

Differential Essential (Differential Fluid Exchange)

April 6, 2025

What's the dif? To an automotive technician, it's the differential, a part of your vehicle that helps direct power from the engine to the wheels. The differential is a gearbox that enables the drive wheels to turn at different speeds (they do that when you turn). Inside the differential is a f... More

Motor Oil?The Synthetic Advantage (Synthetic oil vs Conventional)

March 30, 2025

Youve probably already heard that regular oil changes are extremely important for the health of your vehicles engine. Thats sound advice. But what you might not know is when it comes to motor oil, the real thing may not be the best thing for your engine. There are different types of motor oil: ... More