Mack ASET AC - Cooling System Service Procedures (In-Chassis); Thermostat Replacement

REPAIR INSTRUCTIONS, PART 2
Page 391
COOLING SYSTEM SERVICE
PROCEDURES (IN-CHASSIS)
Thermostat Replacement
[215 NU, NG & LD]
The EGR mixer tube must be removed to gain
access to the thermostat housing for replacement
of the thermostats. Once the mixer tube is
removed, proceed as follows:
Allow the cooling system to cool completely
before attempting to remove the thermostat or
thermostat housing. To avoid injury when
removing the pressure cap from the surge
tank, turn the cap counterclockwise to the
first stop, but do not depress. Allow pressure
to dissipate completely, and then press on the
cap downward and continue turning to
remove.
THERMOSTAT HOUSING REMOVAL
[215 NG & NU]
1. Loosen the hose clamp for the surge tank
port at the side of the thermostat housing.
Allow the surge tank to drain into an
approved container and save the coolant for
reuse.
2. Loosen the hose clamps and disconnect the
bypass and radiator hoses at the front of the
thermostat housing (Figure 465).
465
Figure 465 — Thermostat Housing Hose Connections
3. Remove the cab heater and optional fuel
heater coolant return hoses from the
thermostat housing (if applicable). The cab
heater and optional fuel heater coolant
return hoses were relocated from the
thermostat housing to the radiator lower
tube in mid-2004.
4. Loosen and remove the three mounting
capscrews from the thermostat housing.
1. Bypass Hose
2. Radiator Hose Port
3. Surge Tank Port
5-111.bk Page 391 Monday, July 10, 2006 2:26 PM