Mityvac MV4525 COOLING SYSTEM TEST & REFILL KIT - Manual (Page 8)

Temperature Testing (Engine On)
For diagnosing:
Thermostat
Cooling fan and related components
Coolant sensor
Set-up & Procedure:
1. Ensure the cooling system is cool and not pressurized. Carefully
remove the radiator or coolant bottle pressure cap (Fig. 9).
2. Check to see that the radiator or coolant bottle is filled to the
proper level, and check hoses for visual damage or leaks. Fill
and repair as necessary prior to testing.
3. Select the correct Cooling System Adapter for the application.
Refer to the Adapter Selection Guide included in the kit.
4. Apply water or coolant to the rubber gasket and/or o-ring on
the adapter, and install the adapter in place of the pressure
cap (Fig. 10).
5. Install the Valve Coupler onto the system adapter using the
quick-connect. Make sure the quick-connect sleeve snaps
forward to lock the connection (Fig. 11).
6. Loosen the threaded cap on top of the Valve Coupler, and remove
the Plug if necessary. Insert the Temperature Probe through the
Valve Coupler, and adjust the depth of the probe to ensure it is in
contact with the coolant in the bottle or radiator (Fig. 12). Do not
force the probe down so hard that it damages the probe,
radiator, or coolant bottle.
7. Tighten the cap on the Valve Coupler to form a seal around the
Temperature Probe and hold it securely.
8. Ensure the Shuttle Valve on the Valve Coupler is shifted to the
“Closed” position. (Fig. 13).
9. Start the vehicle engine and monitor the probe reading as the
engine rises to operating temperature. Compare the results to
the diagnosis below to determine proper function of thermostat,
cooling fan sensor/relay, and coolant temperature sensor.
Thermostat
When the thermostat opens, the temperature will surge as hot
coolant from the engine flows into the radiator or bottle. Note
the peak temperature during this surge and compare it to the
manufacturer’s thermostat specification. If the reading is not
within a few degrees of the specification, the thermostat is
faulty and should be replaced.
If the temperature reading on the probe does not increase as the
engine warms, this may indicate the thermostat is stuck closed,
and should be replaced.
If the reading on the probe increases very slowly and will not
reach the thermostat opening temperature, the thermostat may
be stuck open, and should be replaced.
Cooling Fan(s)
If the vehicle has electric fan(s), note the temperature at which
they cycle on and off. Verify this reading against the manufacturer’s
specification. If it’s within a few degrees, the cooling fan sensor(s)
are functioning properly. If the fan(s) do not cycle on and off,
check the fuse(s), motor(s), switch(s), and relay(s) to determine
possible cause(s).
continued on next page
Page Number - 8 Form 822947
Fig. 13
Fig. 9
Fig. 10
Fig. 11
Fig. 12