Mityvac MV4525 COOLING SYSTEM TEST & REFILL KIT - Manual (Page 6)

Applications & Basics of Testing
The MV4525 Cooling System Test & Refill Kit includes equip-
ment to test and monitor pressure, temperature and vacuum
simultaneously to perform a complete cooling system analysis.
It is capable of performing diagnostic tests with either the
engine off or engine on. While engine off tests are quick and
reliable, testing with the engine on more accurately represents
the conditions under which cooling system failures occur, and
greatly expands the types of failures that can be diagnosed.
Engine “Off” Testing
Cooling system leaks are a common cause of overheating, and
can be quickly and easily diagnosed without running the engine.
With the MV4525, the user can choose to apply either pressure
or vacuum to the system, and then monitor it for a short period
of time to determine if a leak exists. Pressure is most commonly
used to perform this test because it will force fluid to seep from
any external leak, making it easy to identify.
For convenience, a vacuum leak test is usually performed in
conjunction with a vacuum refill. A vacuum refill is performed
with the engine off, and is a quick and effective way to refill the
cooling system without trapping air. A vacuum leak test and
refill is performed after the cooling system has been drained.
A compressed air operated vacuum is used to remove all air
from the empty system, and then the system is monitored to
determine if there are any leaks. If no leaks are present, the
vacuum is used to automatically draw in new fluid, and fill the
system without reintroducing air.
Testing proper function of the cooling system pressure cap is
another test that is performed with the engine off. All pressure
caps have a built-in vent designed to release pressure from the
cooling system when it exceeds a maximum value. The proper
function of this cap is critical to preventing failures caused by
under- or over-pressurization. This test is performed using the
pressure pump and gauge included in this kit, however it also
requires cap test adapters that are not included with this kit, and
must be purchased separately. Refer to the Adapter Selection
Guide included in the kit for more information on cap adapters.
Engine “On” Testing
Simultaneously monitoring pressure, vacuum, and temperature
when the engine is first started, and while it progresses towards,
or cools down from, normal operating temperature, provides
extensive information that is invaluable to diagnosing cooling
system related problems. Performing an engine-on test using
the MV4525 can quickly diagnose a blown head gasket or
cracked or damaged block or head. It can also indicate a faulty
thermostat, fan switch/relay, or coolant sensor. In addition, some
system leaks may only be evident during an engine’s normal
operational warm-up and cool-down cycle. The procedures in
this manual will illustrate how to perform engine-on tests as well
as diagnose the results.
Precautions
This equipment is designed for servicing a variety of vehicles
in a safe, convenient manner. However, differences in cooling
systems may make it impossible to perform some of the tests
indicated in these instructions on every vehicle. The procedures
documented in this manual are to serve as guidelines for the
use of this equipment. In addition to these guidelines, always
follow the manufacturer’s recommended procedures when
servicing each unique vehicle. Do not attempt to force a test
on a cooling system for which this equipment is not designed
to perform.
Performing cooling system tests using the MV4525 is simple
and straightforward if you follow the instructions. However,
always keep in mind that you are working with a system that
may be full of hot, pressurized fluid that is just waiting to be
expelled. The MV4525 has safety valves built-in at every possible
connection, but if you are testing an engine that is hot and/or
pressurized, always stop to think before disconnecting a hose
or other component, or shifting a valve.
Always read carefully and understand instructions prior to using
this equipment.
Always wear eye protection when removing the radiator or
coolant bottle cap, or when performing any cooling system test.
Never remove the radiator or coolant bottle cap, or attempt to
pressurize the cooling system of a vehicle that is overheated.
Always allow system to cool prior to attempting to perform any
cooling system related test procedure.
Basics of Testing
When deciding where to connect to the cooling system,
first look for the radiator and determine if it has a fill neck
and pressure cap. This is common on about half of U.S.
manufactured vehicles, and almost all Asian manufactured
vehicles, and would be the first choice for connecting. If the
radiator is closed and inaccessible, then the connection will
be made through a coolant bottle. Some automotive cooling
systems utilize a coolant overflow bottle that is not part of the
sealed system. Attempting to test the cooling system through
this bottle will not connect you into the sealed system, and will
simply vent the test pressure or vacuum to the atmosphere.
This type of overflow bottle is easily recognized because it
typically utilizes a snap-on style cap or a threaded cap that is
open to atmosphere. There are no adapters that are designed
to fit this type of coolant overflow bottle. A test connection
should be made through a radiator or coolant bottle with a
bayonet or threaded style of cap designed to maintain a
specific pressure in the cooling system.
Adapters
The MV4525 includes four cooling system adapters that fit
the radiators and coolant bottles on the vast majority of U.S.
and Asian manufactured vehicles, and even some European
vehicles. An adapter is required to connect the test equipment
to the specific make and model being tested. Once the correct
adapter is identified for the test vehicle, it can be used to
perform all of the tests outlined in this manual except for the
cap pressure test. To perform a test on a vehicle application not
covered by one the four included adapters, or to perform a cap
pressure test, additional adapters must be purchased. Adapters
are available for virtually every make and model of car, and can
be purchased individually or as part of an adapter kit from
Mityvac Tools. Refer to the Adapter Selection Guide included in
the kit for more information on adapters.
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