V.T.E. S.r.l.
OWNERS MANUAL
PAGURO 12500
23
7. COOLING SYSTEM
RAW WATER COOLING SYSTEM
The raw water flow is created by a positive displacement impeller pump. This pump draws cooling water directly from the
raw water source (ocean, lake or river) through a hose.
The raw water is pumped to the oil cooler in the sump. The water flows from the oil cooler to the heat exchanger. From the
heat exchanger discharges into the water-injected exhaust manifold where it mixes with and cools the exhaust gasses.
COOLANT TEMPERATURE SWITCH
The coolant temperature switch is located near the thermostat housing (see illustration). If the coolant's operating
temperature reaches approximately 99°C this switch will light up the red (LED) engine overheat indicator on the control panel
and shut down the generator.
RAW WATER PUMP
The raw water pump is a self-priming, rotary pump with a non-ferrous housing and a neoprene impeller. The impeller has
flexible vanes which wipe against a curved cam plate within the impeller housing, producing the pumping action. On no
account should this pump be run dry as water acts as a lubricant for the impeller. There should always be a spare impeller
and impeller cover gasket (an impeller kit) onboard. Raw water pump impeller failures occur when lubricant (raw water) is
not present during engine operation. Such failures are not warrantable and operators are cautioned to make sure raw water
flow is present at start-up. The neoprene impeller has a limited lifetime and must be inspected regularly.
NOTE: should a failure occur with the pump's internal parts (seals and bearings), it may be more cost effective to purchase a
new pump and rebuild the original pump as a spare.
Inspecting / Changing the Raw Water Pump Impeller
Close the raw water intake valve. Remove the pump cover
and, with the aid of two small screwdriver, carefully pry
the impeller out of the pump. Install the new impeller and
gasket. Move the blades to conform to the curved cam
plate and push the impeller into the pump's housing.
When assembly, apply a thin coating of lubricant to the
impeller and gasket. Open the raw water intake valve.
NOTE: never allow the pump to run dry. Even a short
period of dry running may destroy the impeller.
RAW WATER INTAKE STRAINER
NOTE: always install the strainer at or below the waterline so the strainer will always be self-priming.
A clean raw water intake strainer is a vital component of the engine's cooling system. Include a visual inspection of this
strainer when making your periodic engine check. The water in the glass should be clear.
Perform the following maintenance after every 100 hours of operation:
1. Close the raw water seacock.
2. Remove and clean the strainer filter.
3. Clean the glass.
4. Replace the sealing washer if necessary.
5. Reassemble and install the strainer.
6. Open the seacock.
7. Run the engine and check for leaks.
NOTE: also follow the above procedure after having run hard aground.
If the engine temperature gauge ever shows higher than normal reading, the cause may be that silt, leaves or grass may have
been caught up in the strainer, slowing the flow of raw water through the cooling system.
