Mityvac 04700 AirEvac - Manual (Page 4)

Page Number - 4 Form 823538
Figure 2
6. Turn the tension knob clockwise to
expand the rubber body until it comes
into firm contact with the interior wall
of the radiator or expansion tank filler
neck.
7. Check the connection by holding the
radiator or expansion tank stable
while carefully attempting to pull up
on the adapter. If the adapter comes
free or is not snug, increase the ten-
sion by further rotating the tension
knob.
Caution: Some late-model vehicles
are equipped with radiators or
coolant expansion tanks made of
plastic. Excessive over-tightening
(expansion) of the rubber adapter
could result in cracking the radia-
tor or expansion tank. Use caution
when tightening the expandable
rubber adapter.
8. Utilizing the quick coupler connection,
connect the Vacuum Pump Assembly
to the Cooling System Adapter As-
sembly. (See Figure 3.)
9. Connect clean, dry, regulated com-
pressed air between 90 and 120 psi
(6.2 to 8.3 bar), to the Vacuum Pump
Assembly by means of the previously
installed air coupler nipple.
Figure 3
10. Turn on the compressed air, and
open the flow control valve on the
Cooling System Adapter Assembly.
The venturi action of the vacuum
pump will make a hissing noise as air
is removed from the cooling system.
If the cooling system is not empty,
coolant may be sucked through the
vacuum pump and sputter from the
muffler.
11. While watching the gauge, allow the
vacuum pump to pull air from the
cooling system until it reaches 24 to
26 in. Hg (81 to 88 kPa). This pro-
cess should take less than a minute.
Note: As air is evacuated from the
cooling system, it is normal for radia-
tor hoses to collapse. If the system
fails to pull a vacuum, check to see
if there are any overflow hoses that
need to be clamped off in order to
produce a closed system.
12. Once the cooling system has reached
24 to 26 in. Hg (81 to 88 kPa) vacu-
um, close the valve on the Cooling
System Adapter Assembly, discon-
nect the air supply, and then discon-
nect the Vacuum Pump Assembly.