Chapter 3 HVAC Tools, Equipment, and Service Information 57
they are complex and vary between manufacturers. Minor
changes may be made between model years, often chang-
ing diagnostic and service procedures. The service literature
described in the following paragraphs can simplify HVAC
service by providing the latest information.
Factory Manual
The factory manual is published by the vehicle
manufacturer or a publishing house contracted by the
manufacturer. It contains all necessary service informa-
tion for that one vehicle. Figure 3-40 shows some typical
factory service information. Most modern factory service
information now comes in volume sets for one vehicle.
The major drawback to the factory manual is its relatively
high cost, compared to the limited range of vehicles it
can be used with. While this type of manual is extremely
detailed, it may not be the best choice if only one system,
such as the brakes, is to be serviced.
General Manual
The general manual contains the most commonly
needed service information about many different makes of
vehicles, such as brake, engine, and transmission specifi ca-
tions, fuse replacement data, and sensor locations. General
manuals also contain procedures for preventive mainte-
nance and minor repairs.
At one time, general service information for every
vehicle could be covered in one manual. Today, due to
the large number of different vehicles available, this is
no longer possible. Modern general manuals are divided
into automobile and light truck editions. Publishers further
divide their general automotive manuals into US, European,
and Asian models.
The individual chapters of general manuals are
grouped according to vehicle make, or several makes that
are similar mechanically. Chapter subsections are devoted
to particular areas of each make. General manuals also
contain separate sections covering repair procedures that
apply to all vehicles, such as engine overhaul, brake ser-
vice, and starter/alternator overhaul. The major disadvan-
tage of these manuals is the necessity of eliminating most
of the information on specialized vehicle equipment, sheet
metal, and interior.
Specialized Manual
Specialized manuals cover one common system of
many types of vehicle. These manuals are often used to
cover such topics as computerized engine controls, elec-
trical systems, or brakes. They combine some of the best
features of the factory and general manuals. They are often
a good choice for servicing one particular system on many
different makes and models of vehicles. One example of
this type of manual is shown in Figure 3-41.
Figure 3-39. A combustion leak tester may be needed to deter-
mine whether a cracked engine component or leaking gasket is
causing exhaust gases to enter the cooling system. (Snap-On)
Figure 3-40. Factory manuals are used for one vehicle only.
Most newer ones come in volume sets.
(DaimlerChrysler, MVCC, Jack Klasey)
Figure 3-41. Many service information publishers, such as Motor
and Mitchell publish overhaul manuals. In addition, overhaul
manuals are available from vehicle manufacturers.