MACS Monthly Newsletter - 2022 - JAN5

be below 40.
Me: Yes, the pressures are not where they should be for
sure. What were the pressure readings with the previous
compressor?
Him: About the same.
Me: And what were the pressure readings with the original
compressor?
Him: About the same.
Me: So, if I'm understanding this correctly, there have
been 3 compressors on this car (including the original
unit) and you've gotten the same results with all 3. Is that
correct?
Him: Actually, there was one more. I got a unit from one
Figure 7: This is a typical reading that can be expected
when taking temperature readings on an A/C system with
an infrared temperature gun. Both the infrared gun on the
left and the contact type temperature reading tool on the
right are reading the temperature on the same metal suction
line about ½-inch apart. Before doing the test, I felt
the suction line with my hand, and it felt like a glass of iced
tea. The reading on the contact type temperature reading
tool indicates a temperature that would be expected of a
glass of iced tea. However, the infrared gun indicates a
temperature that is almost 40° higher. This was despite
numerous efforts to get an accurate reading with it and
was the lowest temperature recorded.
Me: Any parts supplier can have a problem with an A/C
compressor, and we certainly aren't an exception, however
we make efforts to ensure that our compressor suppliers
furnish us with high quality product. I understand
that you've had multiple compressors on that car and that
usually is an indication of a problem with the system on
the vehicle and not a compressor problem. Can you tell
me what's going on with this car so I can get a good understanding
of the problem?
Him: I really don't want to waste time talking about it. I
just want another compressor and your warehouse manager
doesn't want to send me one.
Me: The warehouse manager is fine with sending you
another compressor if there is a problem with the current
unit. But, he wants to be sure there is indeed a problem
with it before doing so and I'm sure you don't want to
spend time replacing a compressor unnecessarily. You've
obviously spent a lot of time already working on this car,
but maybe spending a few minutes explaining what is going
on with it could be a good investment of time.
Him: Well, OK. This compressor just won't pump like it's
supposed to. It will only create about 135 to 140 psi on the
high side and will only pull the low side down to about 60
or 65 and it isn't doing much cooling.
Me: What was the ambient temperature when those
pressure readings were taken?
Him: It was a little earlier today and it been about 90°
most of the day. The high side pressure should be more
along the lines of about 180 to 225 and the low side should
January 2022
5
Figure 8: Honda suction hose. The straight metal tubing
on one end and almost straight metal tubing on the other
end made it easy to see daylight when looking through it,
but it didn't look perfectly round on the inside.
MACS Service Reports
of your competitors and it leaked, so I had to return it.
Me: What were the pressure readings with that one?
Him: Same thing.
Me: So, we're talking four compressors and they are all
doing the same thing?
Him: Yes.
Me: What do you think the chances are of having 4 different
compressors all with the same problem?
Him: Well, I'd have to say pretty unlikely.
Me: Exactly. I can almost guarantee you there is a system
problem that is causing those readings and the cooling
problem. Replacing the current compressor isn't going
to fix the problem.
Him: But that compressor just won't pump properly.
(SLAMMING HIS FIST ON THE DESK!)
Me: I understand your frustration and why those pressure
readings were the reason you initially replaced the
compressor, but here we are 2 additional compressors
Richard Hawkins
Richard Hawkins
MACS Monthly Newsletter - 2022

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