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Requirements for the Use of Coolant for Diesel Generator Set

Nov. 15, 2019

What are the requirements for the use of coolant in a diesel generator set?

When the diesel generator set is running, there are certain requirements for the coolant to ensure that the cooling system components and even the whole machine can work normally.

D114 series diesel generator engine coolant should be a mixture of antifreeze and DCA4 chemical additives or water and DCA4 chemical additives (the temperature of the diesel engine is always greater than O°C).

Note: Some models may not require the use of DCA4 additives.

Since antifreeze prevents freezing of the coolant and increases the boiling point of the coolant, Starlight Power requires antifreeze to be used in any climate.


Prepare the coolant water, can use rainwater, lake water, river water or tap water. When using river water and lake water, it should be clarified to remove impurities such as dust and sediment from the water. For the areas with water source shortage, if well water or groundwater is used, because the hardness of the water is high, heating boiling method (boiling precipitation of water) and adding alkali method (0.67g caustic soda per liter of water, stirring precipitation) should be used to soften the hardness of the water.


Adjust the water and glycol and mixing ratio to get antifreeze at different freezing points (that is freezing point). For most climates, we recommend a 50:50 ratio of water to glycol. The concentration of ethylene glycol in the acceptable antifreeze solution is preferably in the range of 40-60%. Under normal circumstances, the freezing point of the selected antifreeze should be about 10°C lower than the lowest temperature in the area where the diesel engine is in use.

The freezing point of the antifreeze can be accurately inspected by a refractometer, or it can be measured by special test paper for measuring the freezing point of the antifreeze.

Note: It is necessary to release and replace new antifreeze every 6000h or 2 years (whichever comes first) to remove harmful chemical deposits.

diesel generator set

DCA4 chemical additive

The DCA4 chemical additive has anti-cavitation, anti-corrosion, anti-fouling, and anti-bubble formation protection for the diesel engine cooling system. Starlight recommends the use of Shangchai D114 Series B diesel engine and regularly replace the DCA4 additive.

D114 series diesel engine coolant has certain requirements for the concentration of added DCA4 chemical additive: 0.264 units of DCA4 chemical additive per liter of coolant, but the maximum is not more than 0.528 units, and the minimum cannot be less than 0.132 units. The DCA4 chemical additive per unit weighs 22.68 grams. For example, a diesel engine with a total cooling capacity of 30 liters should be fitted with a water filter containing 12 units of solid DCA4 chemical additive, such that each liter of coolant contains 0.400 units of additive.

In order to make the DCA4 chemical additive in the diesel generator coolant meet the above concentration requirements, a water filter containing a solid DCA4 chemical additive with a similar number of units should be installed.

Note: When the water filter is added with powder DCA4 chemical additive, the total content of DCA4 chemical additive in the coolant should not exceed the specified maximum value (0.528 units / liter).

Water filter

The water filter has two functions: one is that it has a certain amount of DCA4 additive, the coolant has a prescribed concentration of DCA4 additive; the other is to filter the impurities in the coolant. Therefore, it is recommended that the DCA4 water filter be replaced regularly.

Note: The DCA4 water filter (coolant filter) must be replaced every 250h or 3 months (whichever comes first).

DCA4 additive concentration check

The DCA4 water filter should be replaced at regular intervals to ensure that the coolant has the appropriate DCA4 additive concentration, or that the DCA additive concentration should be checked periodically.

Inspection method

The concentration of DCA4 additive in the coolant was measured using the DCA4 additive concentration test kit provided in the random spare parts box. The detection method is as follows:

1. Take half a cup of diesel engine coolant from the large plastic cup in the test kit/package and let it cool to room temperature.

2. The diesel engine coolant from the large plastic cup is sucked to the top of the straw with the straw in the test bag and injected into the small plastic cup in the test bag.

3. Place the small plastic cup in the horizontal position of the line of sight and fill it with #1 solution in the test bag to the specified mark line position, then shake the small plastic cup to mix the #1 solution with the diesel engine coolant.

4. Dip a molybdate test paper A into a small plastic cup, and immediately take out and shake off the excess coolant; Repeat the above test with nitrous acid test paper B.

5. Allow the color change on the test paper for one minute (but not more than two minutes), then test paper A and the test paper B are placed in the comparison color box of the color card of the coolant concentration control in the the test pack for comparison.

6. By determining the cross-frame of the test paper A and the test paper B on the color card, it is possible to determine whether the coolant concentration is within the specified test range.

7. After the test, clean the used containers and straws with clean tap water.

The effect of coolant on the operation of diesel generator set

The diesel engine generator is affected by the combustion of its own diesel fuel, which will cause the diesel engine temperature to rise sharply. In the high temperature environment, it will not only affect the working efficiency of the diesel generator, but also cause the failure of parts and components. Therefore, we need to cool the heated part, what effect does the coolant have on the operation of the diesel generator set?

First, antifreeze effect. Under the condition of too low temperature, the cooling system of the diesel engine is not frozen. Generally, the commonly used coolant antifreeze temperature is between minus 20 degrees to 45 degrees, which is reasonably selected according to the actual needs of different regions.

Second, anti-boiling effect. At high temperatures, there is no premature boiling. The boiling point of the commonly used coolant is between 104 to 108 degrees. When the coolant is added to the cooling system and pressure is generated, the boiling point will be higher.

Third, antiseptic effect. Special coolant can reduce the corrosion of the cooling system and avoid water leakage caused by the corrosion of the cooling system.

Fourth, anti-rust effect. High quality coolant can prevent the cooling system from getting rusty. Once the cooling system rusts, it will cause accelerated wear and reduced heat transfer efficiency.

Fifth, anti-scaling effect. Since the coolant is deionized water, it can avoid the formation of scale and sediment, and achieve the purpose of protecting the engine.

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