TM 55-1930-203-10
b.
Refueling the LARC.
WARNING
When refueling, secure the electrical system by placing master switch (19, sheet 2, fig. 2-1) in
off position. Observe the no smoking signs. Do not permit anyone to operate tools or
equipment which may produce sparks near the refueling operation. Observe the usual
procedure for grounding static electricity. Sparks or fire may ignite the fuel and produce an
explosion.
(1) Before each mission and on extended operations, check fuel level in tanks and top off as necessary. During the
fueling, observe all safety precautions. Post notices that a fueling operation is in progress and that no smoking is permitted.
(2) To refuel the LARC, proceed as follows:
(a) Secure the electrical system of the LARC.
(b) Remove vent plug (2, fig. 3-20) and fill plug (5).
NOTE
A dipstick may be inserted into the fill plug part to determine how much fuel is required to fill the tank.
(c) Connect the fuel hose to the fill plug port, and ground the hose nozzle to the LARC with the clip provided. Proceed
with the fueling, monitoring the operation by checking the liquid level gage (7).
(d) When the tanks have been topped off, coat the threads of the fill plug and vent plug with white lead and replace.
3-16. Water Cooling System.
a. General.
The LARC cooling system (fig. 3-21) consists of
four independent fresh water cooling systems. The cooling
systems function independently of each other so that failure of any one engine air cooling system will not affect the operation of the
remaining systems. The water pump mounted on each engine draws coolant from the oil cooler and circulates the coolant through
the engine into the expansion tank (2). Coolant from the expansion tank flows through the radiator (1), cooling coils (4), and heat
exchangers (3), back to the engine. Two oil-to-water heat exchangers (3) are connected in parallel in each engine cooling system.
They are used for cooling the marine gear and gathering box lubricating oil. During land operation, the coolant in the cooling system
is cooled by radiators and hydraulically operated fans mounted in the aft section of the LARC. The fans blow air through the radiator
openings to cool the coolant within the radiator cores. Air passing through the radiator core openings is expelled to the atmosphere
through the radiator stern louvers installed on the aft end of the LARC. During marine operation, cooling is accomplished by cooling
coils (4) located in aft wheel wells which are submerged during water operation. The cooling effect of the outside water is transmitted
to the engine coolant as it circulates through the coils.
1 Radiator
2 Expansion tank 3 Heat exchangers 4 Cooling Coils 5 Drain plugs
6 Seat cover 7 Storage
8 Plug
Figure 3-21. Engine cooling system.
Change 4
3-49