Some of our technicians have been working in the automotive industry for many years, and they still encounter new problems.
A unique issue was discovered on a GMC Terrain. Our customer brought the SUV in because they could hear a screeching noise while driving. This sound was coming from the passenger side and would get progressively louder as they were changing gears.
So began the diagnostic testing process.
How did we find the source of the screeching noise?
The noise was very noticeable when our technician started working on the GMC Terrain.
When the serpentine belt was taken off, the sound went away. So, he knew the problem had something to do with the air conditioning compressor.
The compressor creates pressure in the air conditioning system, compressing the refrigerant.
After removing the belt, the technician realized the clutch on the AC compressor was damaged and determined that it had failed.
We replaced the compressor and the serpentine belt. This belt wraps around your accessories, such as the alternator, compressor and – if the car has hydraulic power steering – the power steering pump. It’s a good idea to replace it while we’re there.
Diagnostic testing will look differently for each car. It can include visual inspections, test drives, receiving assistance from tools, and using the process of elimination to track down the culprit.

What AC compressor problems can occur?
The problem we saw on the GMC Terrain isn’t a common one. In fact, our technician hasn’t seen it happen before.
AC compressor clutches engage the pulley to the compressor.
They could go bad, but normally because they wear out. The clutch coil may burn out, keeping it from engaging or unengaging.
An internal compressor problem is also possible. The compressor can get dragged down or locked up, or it might become worn enough that it doesn’t compress enough pressure.
How do I know if my AC compressor clutch is bad?
Like the GMC Terrain owner, drivers might notice symptoms when there’s a problem with the AC compressor or compressor clutch.
If the clutch coil is wearing out, it could engage or unengage sporadically.
You can listen for noises, too. Sometimes, the air conditioning compressor or AC compressor clutch will start chattering.
Air conditioning problems may also indicate that something is wrong with the compressor or clutch. (Keep in mind that a compressor going bad is just one of many possible causes behind car AC problems.)
If you’re hearing a sound you don’t recognize or a system isn’t working how it’s supposed to, it’s worth having the problem checked out. There may be an issue that worsens or impacts you later on.
In the case of the GMC Terrain, our customer can now enjoy a quieter ride and expect to have a working air conditioning system come summertime.
HomeTowne Auto Repair & Tire is an authorized Michelin and BFGoodrich tire dealer located near Dumfries, Virginia. Automotive repair services are performed on all makes and models, including oil changes, brakes, alignments, inspections, and computer engine diagnostics.













