MACS Service Reports - 2015 - MAY5

The issues

Delphi

We'd also caution that just because a compressor
is new doesn't mean its quality is better than a quality reman. The rule: know your supplier (and check
the warranty, including who's behind it).

One of the most common problems is that parts
may have to be transferred from the original compressor, and that can result in problems. Pulling
off a switch, for example, may result
in a cracked plastic housing. If you
don't realize it, that could be bad
news. Even if you do, you may have
trouble, or at least a delay that could
be days until you get a new one. As
some unlucky technicians can tell
you, that replacement may fit, but
its calibration applies to a different model year. If it's a fan switch,
for example, it may not close at the
right pressure for that compressor
or vehicle system. So don't just pull
off the old switch. Take a close look
at the mount, and be gentle. In fact,
you might want to see if there's a special puller for safe removal. Santech
(santech.com) for example, makes a
puller for oval compressor switches
on Chrysler and General Motors applications and another for round GM
Figure 5: Variable displacement compressors may have a mechanical control valve or an external
switches
and you may be able to get
solenoid valve duty-cycled by the HVAC control module (or another module). This particular
them
from
local auto parts stores.
Delphi compressor was designed to accommodate either control valve, easily serviced.
The compressor output control solenoid valve is another example (Figure 5). Some are internal, all-mechanical valves that
In the past year, we've noted some cases where the control displacement, but the external valve with
compressor clutch can be replaced on the car (actu- computer control has become more widely used.
ally that used to be the most common way until the Both are replaceable, and if they are the problem,
powertrain compartments got really crowded). In you could change out the compressor, move the old
that case, an obviously bad clutch is more easily re- valve to the new compressor and still not fix the
placed (and more economically) than changing the problem. The external control solenoid type, a Dencompressor.
so five-cylinder design, is installed on many ToyoBut for the most part, the ready availability of ta and Chrysler products, and more recently on a
low-cost, new compressors, often sourced from Delphi CVC unit. If the compressor doesn't change
Asia, made it simpler to remove and replace. The stroke with changes in cooling load, the suspicion
durability may not match the OE's. But hey, if it is likely on that solenoid valve. Some scan tools can
goes 2-3 years, that gets you past any shop war- diagnose this system, but not likely the aftermarranty and the lower price vs. OE can be acceptable ket scan tool you have. So the primary aftermarket
all around, particularly if the car is likely to end choice for diagnosis is the duty cycle tester, which
up with another owner in that time period. In such MACS Service Reports has covered and now that
a case, you have to know your customer and what there's a second tester on the market, you'll find
he expects. Be upfront about a low-cost aftermarket both in the May 2015 issue of ACtion magazine, in
compressor and what to expect.
the tool and equipment review. The basic tester is
We should also point out there are some popular the CLT1, (clt1.com); the more elaborate ECCS06
compressor numbers that are used in high-enough unit, which has additional functionality, is sold by
volume that small makers can devote a line to pro- Global Parts Distributors (globalpartsdist.com). See
ducing new replacements and offer decent quality.
Figures 6 & 7.
As we see more frequently, however, replacing
Another nice aspect of the external solenoid valve
that compressor may not always be the best answer is that it can be more positively diagnosed for a sysor the total answer whether you're installing a re- tem failure. When we say more positively, we don't
man, a new OE or any aftermarket replacement.
mean it's necessarily easy. Yes, either of the testers
can diagnose a defective solenoid valve. And the

May 2015

MACS Service Reports

http://www.santech.com/ http://www.clt1.com http://www.globalpartsdist.com

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