Diesel engines are heat-generating sources. They are cooled by circulating a water-based coolant through a water jacket, which is part of the engine. The coolant is circulated through pipes to the radiator to remove the heat added to the coolant by the engine and then back to the engine.

The typically components of the cooling system are:

1. Water pumps

2. Heat removing device (radiator or heat exchanger)

3. Coolant expansion tanks (surge tanks)

4. Temperature control valves

5. Temperature and pressure switches and indicators

6. Pipes

Please note that the engine water cooling systems are either closed or open systems. Closed system is designed to use the same coolant with a closed circuit, preventing the losses of the coolant. While the open system uses the coolant once and discharges it or recirculates the coolant through systems, which cool the coolant by evaporation. Most of the stationary diesel engines use closed systems to control the chemistry of the coolant to prevent fouling of heat transfer surfaces and to closely control the temperatures.

In general, diesel generator cooling system has the following functions:

1. Cooling the engine cylinders via water jacket

2. Cooling the lube oil via lube oil cooler

3. Cooling combustion air via after cooler on turbo-charged engines

Although there are various types of pumps used in diesel engine cooling systems, two pumps are often used for two circuits systems. One is Engine driven pump, the other is electrical driven pump (It is used to circulate the coolant to keep the engine warm when the engine is not running.)

A high-powered diesel engine is very hard on the coolant. Additive-depleted coolant will not only allow liner cavitation but cause premature failure of the head gaskets, radiator, water pump, freeze plugs, heater core and thermostat.

Maintenance

Many diesel engines issues are caused by lacking proper maintenance.

First, check the additive level should be a part of maintenance schedule. Since the diesel engines have such a large liquid capacity, cooling system test strips are offered to check the level of additives. If the level is low, a bottle of SCA can be mixed in to renew the coolant without a complete change.

Second, when you are going to buy coolant, make sure it is compatible with a diesel engine, not automotive or light-truck use, which means gasoline powered.