MACS Service Reports - 2016 - MAY1

Total Vehicle Climate and Thermal ManagementTM

May 2016

By Paul Weissler, MACS Senior Technical Correspondent
THE SO-CALLED "DOG JOBS"

tools. And the special tools needed for Mercedes-Benz and
Toyota couplings also have been readily available in the aftermarket for years.
The Toyota tool, used on many cars since 1998, is an interesting situation. The OE-approved tool set (from OTC Tools)
is a neat design that incorporates safety latching, etc., but it's
expensive. So long as you have the system empty, all you
really need is a simple tool, basically a modified flat-blade
screwdriver - that goes in and releases the plastic tabs (Figure 1). This type of tool has been made by a few manufacturers, and OTC Tools still offers one (No. 6073).
Paul Weissler

We've all become accustomed to having to deal with the
dog job. If you know about it in advance, you can quote
an appropriate estimate. It's one thing to quote low on a job
with minor complications, that takes an extra half hour and
involves some struggling. But there's obviously nothing
worse than under-quoting by a large margin and having to
struggle too. And there's even a way for the job to get completely out of hand - because it requires a special tool.
We hear a lot of complaints about the special tools. "Why
the hell did they design it this way?" is a common refrain, so
we thought we'd discuss the subject in those terms.
Perhaps the most common reason is ease of assembly at
the manufacturing level. Instead of trying to have an assembly line worker, or even a robot, install screws into deeply
recessed holes, the part is designed with slots and a mating
part that aligns with them and has locking plastic or metal
tabs. So all the assembly line has to do is push the two parts
together and the tabs fit into the slots and lock the two pieces
together. Even where the access is good, the quick snaptogether ensures assembly accuracy and saves time on the
assembly line - the spring-lock coupling, much-maligned,
is a perfect example on the A/C system. Several evaporator temperature sensors snap into plastic retaining tabs - no
guesswork.
Of course this approach to engineering design creates a
disassembly issue. The most noteworthy one was solved
easily enough with the inexpensive spring-lock coupling

Figure 1: Several inexpensive tools were made to pop open the plastic
clamp used on many Toyota products since 1998. This is the one in our
toolbox, and it has worked just fine. There are others. So you can avoid
the expensive OE tools.

A second major reason is that the engineers have to fit in a lot
of parts in a limited amount of real estate under the hood. So
some parts are going to require removing a lot of other parts, or
reaching into a deeply recessed area where no ordinary tool will
go. When this approach is taken, the engineers have to provide
for a way to service the system, and a special tool is one answer.

ALSO INSIDE THIS ISSUE:
Those Really Special Dealer Tools - Getting Them In Time.................................................................................................... 3
Don't Have The Factory Scan Tool? .............................................................................................................................................. 4
HVAC Odor - Another Wrinkle On The Problem ........................................................................................................................ 5
Lest We Forget ................................................................................................................................................................................... 5
Even The Lower Priced Cars ........................................................................................................................................................... 7
Second Time's The Charm ............................................................................................................................................................... 7

MACS Service Reports is the official technical publication of the
Mobile Air Conditioning Society Worldwide, Inc., P.O. Box 88,
Lansdale, PA 19446. The material published in MACS Service
Reports expresses the views of the contributors and not necessarily that of MACS. Every attempt has been made to ensure

May 2016

the accuracy of the content of MACS Service Reports. MACS,
however, will not be responsible for the accuracy of the information published nor will MACS Worldwide be liable in any way for
injury, labor, parts or other expenses resulting from the use of
information appearing in MACS Service Reports.

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Table of Contents for the Digital Edition of MACS Service Reports - 2016