Professional_Tool_And_Equipment_News_February_2021 - 42

high humidity should produce a noticeable
amount of condensate from the drain. In
my shop, we use the MiST II Ultrasonic
Cleaning unit from CPS Products to help
eliminate mold and mildew smells within
the vehicle's cabin. This device does its
job by introducing nano-droplets of cleaning solution throughout the HVAC air
flow paths.

produce pressure. The oil was dark brown.
Upon disassembly of the compressor, the
swash plate pivoting mechanism was
mechanically seized due to lack of lubrication. See figure 4.

DIAGNOSTICS

Fig 2 - Pyle Thermo-Anemometer.

vehicles may not even have one, but can
be upfitted. According to the Bosch
Automotive Handbook, cabin air filters
have a recommended replacement interval of every 12 months. Take a look at the
owner's manuals on vehicles you service
for more info. If you're in an area where
the vehicle may have been subjected to
environmental conditions like forest fires,
suggesting maintenance is good practice.
Additionally, filters may be checked for
restriction using an anemometer as shown
in figure 2.

Scan tool and sight glass
It's always a good practice to perform a
full vehicle scan when addressing system
complaints. There may be other issues
present that could prevent proper A/C
system operation. Some vehicles may have
an engine-related fault that could inhibit
A/C compressor operation.

Fig 4 - Compressor wear and failure
inspection after cleaning.

PRESSURE AND TEMPERATURE
Pressure measurement is a great start to
assessing system operation. Combining
that data with temperatures is a gateway
to gaining a deeper perspective into the
system's thermodynamic performance.
The ManTooth Wireless Pressure/
Temperature Measurement Kit from
Yellow Jacket, along with your tablet or
smartphone, can help you quickly assess
the A/C system's performance. See
figure 5.

Hoses and connections
You'll want to inspect hoses and connections for the presence of oil as a sign of
leakage. Keep in mind that loose or broken engine mounts can lead to premature
system leaks.
Fig 3 - Visual sight glass

Condensers and evaporator
A/C condensers are frequently subject
to small rocks and other debris. In some
cases, there may be aftermarket screens
that can be added to help prevent damage.
When looking for leaks in the condenser
area, it may be difficult to locate them until
the system is fully charged and operating
under normal pressures and temperatures.
The evaporator can't always be inspected easily, but the evaporator drain can
help in terms of diagnostics. If it becomes
restricted or plugged, mold, mildew, and
corrosion of the evaporator can occur. You
should also inspect the drain with a leak
detector. In some cases, a borescope may
be used to have a look if warranted. A system operating in warm temperatures and

42

PTEN

FEBRUARY 2021

Years ago, most vehicles possessed
sight glass to help the technician check a
system's charge. Although you may come
across some cars still using one, they can be
used to check charge levels and whether the
system contains fluorescent dye. However,
there's another type of sight glass that can
help take a deeper look. Airsept offers
sight glass that can provide technicians
with additional information. See figure 3.
This tool can help assess the internals of the
A/C system.
When analyzing system performance,
the refrigeration oil condition can be very
telling. We had a vehicle once where the
variable displacement compressor wasn't
working properly and was barely able to

www.VehicleServicePros.com

Fig 5 - Electronically Controlled Compressor
Tester alongside the ManTooth

VARIABLE DISPLACEMENT
COMPRESSORS - VDC
The ECCS06 by 4Seasons is a tool that
we've been using in our shop to help
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