Mityvac MV4525 COOLING SYSTEM TEST & REFILL KIT - Manual (Page 11)

Dynamic Pressure/Vacuum/Temperature Test
(Engine On)
For diagnosing:
Cooling system leaks
Cylinder head damage
Blown head gasket
Cracked block
Set-up & Procedure:
1. Ensure the cooling system is cool and not pressurized. Carefully
remove the radiator or coolant bottle pressure cap (Fig. 26).
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. 27).
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. 28).
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. 29). 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. Connect the Compound Gauge to the quick-connect labeled
“Gauge” extending from the Valve Coupler. Note: It may be
more convenient to install an Extension Hose between the
Valve Coupler and the Gauge (Fig. 30).
9. Ensure the shuttle valve on the Valve Coupler is shifted to the
“Closed” position (Fig. 31).
10. Start the engine, and monitor the readings on the compound and
temperature gauges. Pressure and temperature should increase
steadily as the engine warms to normal operating conditions.
A rapid pressure increase followed by a quicker then normal
increase in temperature, indicates significant cylinder compres-
sion leakage into the coolant system, most likely caused by a
blown head gasket. Other indications of a blown head gasket
may be a faster than normal increase in temperature, steam
flowing from the exhaust, and deposits in the oil. If symptoms
indicate a blown head gasket, immediately shut the engine off to
prevent overheating and the possibility of additional damage.
Smaller internal leaks can be caused by a cracked block or
head(s). These leaks may not cause obvious rapid pressure
buildup, but can still be identified and diagnosed. If the pressure
builds to higher than normal readings and/or the pressure gauge
reading fluctuates rapidly, a compression or combustion leak is
present. A gauge reading indicating vacuum can be a cause by
a crack in the intake port or intake valve seat.
continued on next page
Form 822947 Page Number - 11
Fig. 27
Fig. 29
Fig. 31
Fig. 26
Fig. 28
Fig. 30