MACS Service Reports - 2015 - OCT6

into the specifications for the equipment. An identifier has become a necessity because of the multiple refrigerants issue and
the chances of cross-contamination. If you've followed events
in the industry, you've heard of all the counterfeit labeling that
makes a refrigerant purchase something that should be accompanied by a confirming identification. That's the reason for
our longstanding recommendation of using an identifier first.
Yes, that ends up measurably more expensive than buying an
R/R/R machine with one built-in. But unless the shop already
has a premium late-model identifier, it gives a shop the opportunity to make one useful investment first (the identifier), and
add the new machine at a later date, when more R-1234yf cars
are on the road. ■

overall procedure, but they do not double the time required unless something is wrong. We also recognize that
if you're using a built-in identifier, it does add an additional
maintenance requirement for the machine, replacement of
the oxygen sensor in the identifier (Figures 8, 9 and 10). An
error message will be displayed if its service life has reached
a limit as determined by a maintenance algorithm in the
electronic control system of the machine.
No question that the changeover to R-1234yf has added significant cost to this next generation of equipment, both from
the standpoints of equipment design for safety with the mildly
flammable refrigerant and the addition of refrigerant identification. We really didn't have any choice because R-1234yf was approved by EPA with safe use conditions that we had to factor

PINPOINTING THE LOCATION WAS ANOTHER MATTER
Lots of A/C performance problems have somewhat obvious causes, but actually finding an obvious cause isn't always so easy. This case of a 2009 Pontiac Solstice (or its twin
the Saturn Sky) is a good example. The motorist's complaint
was that the A/C worked okay until the ambient temperature hit 90°F and above. Okay, that seems pretty straightforward, but the reason could be in a range of things, from a
weak compressor to an out of calibration expansion valve to
poor front end airflow. However, while the compressor was
working, it was pumping normally and when the cooling
performance dropped, it was because the compressor had
shut off, caused by the tripping of the high-pressure cutout
switch.
Okay, let's check the pressures. Sure enough they are
somewhat higher than normal at the 80°F ambient. But they
go over 300 psi when it's 90°F. As pressures approach 400
psi, the cutout switch does its job. It has to be an airflow
problem, right? Yes it is, but what's causing it?
The technician checks the fan and it seems smooth and
running at high speed. He looks at the condenser and saw no

debris blocking the airflow. Okay, you might want to clean
them anyway, maybe even see if there's debris between the
condenser and radiator. Nothing there. The technician now
is thinking restriction, but where? Probing the system with
his infrared thermometer turns up nothing.
However, like many cars, the primary airflow (or a large
percentage of the total airflow) is through the lower fascia
air intake. Maybe there's something stuck in there? No, but
when he looks he notices that most of the fins have been flattened. Straightening them with a fin comb (or a small screwdriver if you don't have one) is the fix, and in this case it
restored performance.
What could possibly have caused this? We don't know in
this case, but we have seen similar stuff from hitting a curb or
an abutment in a parking lot. In some cases there's a flexible
front-end air deflector that could be dislodged and whacked
against the lower part of the condenser. So also look for a
loose or missing deflector, which in itself can result in lack of
enough airflow through the condenser. ■

IS THERE STILL A CABLE SYSTEM?

October 2015

Although the two cars share a lot of components, there
are numerous differences; body panels, interior and even
(in some years) the engine. ■

mazdaserviceinfo.com

We've talked about the industry-wide change to electrical/electronic control systems for manual as well as Automatic Temperature Control that you may be convinced
there isn't a cable system still in use. We don't know exactly how many, but there is one that's on a popular car:
the Mazda 3. The subject came up when the issue arose of
the cable hook end getting disengaged from the link that
operates the temperature blend door. Turned out to be a
common issue and Mazda did release a reshaped link to
better retain the cable end (Figure 11). Takes just minutes
to replace the link and reconnect the cable, but the design
of the system itself is worth remembering. The remainder
of the system is electrically-controlled.
There's a similar setup for the Hyundai Accent. It uses a
cable for the temperature control and electrical actuators
for the rest of the system. Interestingly, its sister car the
Kia Rio, has an all-electric control for the manual A/C.

Figure 11: Mazda 3 still uses a cable for manual control of temperature.
If cable hook end comes off link, there is a redesigned link that can be installed, or the cable end can be reshaped for more secure retention.

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Table of Contents for the Digital Edition of MACS Service Reports - 2015
