PREVOST X3-45 2016, Руководство по обслуживанию

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Section 05: COOLING SYSTEM
Section 05 Updated Sept.2016 X3-45 Commuter PA1593 DOB 2400-2489
5
When installing a new hose, clean pipe
connections and apply a thin layer of a
non-hardening sealing compound. Replace worn
out clamps or clamps that pinch hoses.
3.1 CONSTANT-TORQUE HOSE CLAMPS ON
COOLANT LINES –VOLVO D13
All hose clamps of 1 3/8" ID and over, used on
the heating and cooling systems, are of the
"Constant-torque" type. These clamps are
worm-driven, made of stainless steel, and
supplied with a series of Belleville spring
washers. They also feature an extended integral
liner that covers the band slots to protect
soft/silicone hoses from damage, and help
maintain consistent sealing pressure.
This type of clamp is designed to automatically
adjust its diameter to compensate for the normal
expansion/contraction of a hose and metal
connection that occurs during vehicle operation
and shutdown. The constant-torque clamp
virtually eliminates coolant losses due to
"Cold
flow" leakage and greatly minimizes clamp
maintenance.
FIGURE 3: COOLANT FLOW TO RADIATOR (VOLVO D13)
3.1.1 Installation
A torque wrench should be used for proper
installation. The recommended torque is 90 to
100 lbf-in. (10 to 11 Nm). The Belleville spring
washer stacks should be nearly collapsed flat
and the screw tip should extend ¼" (6 mm)
beyond the housing (Fig. 4).
CAUTION
The hose clamps will break if over-torqued.
Do not over-tighten, especially during cold
weather when hose has contracted.
FIGURE 4: CONSTANT-TORQUE CLAMP
05037
3.1.2 Maintenance
The constant-torque clamps contain a "Visual
torque check “ feature. When the tip of the screw
is extending ¼" (6 mm) out of the housing, the
clamp is properly installed and maintains a
leak-proof connection. Since the constant-torque
clamp automatically adjusts to keep a consistent
sealing pressure, there is no need to re-torque
hose clamps on a regular basis. During vehicle
operation and shutdown, the screw tip will adjust
according to the temperature and pressure
changes.
Checking for proper torque should be done
at room temperature.
3.2 CONSTANT-TORQUE HOSE CLAMPS ON
CHARGE AIR COOLER (CAC)
If for any reason such as an accident, hose
clamps need to be changed; install and tighten
hose clamps to 10±1 lbf-ft (dry) (Fig. 5).
CAUTION
The hose clamps will break if over-tighten. Do
not over-tighten, especially during cold
weather when hose has contracted.