How to deal with diesel engine scale? Why is there oil in the diesel engine water tank?

The diesel engine's water tank is filled with water for cooling the engine, so it is easy for scale to accumulate on the inner wall. This scale must be cleaned regularly, otherwise it will affect the engine cooling and eventually affect the diesel vehicle. So how can you deal with diesel engine scale?

How to deal with diesel engine scale

The main component of scale is inorganic salt calcium carbonate, etc., such as using alkali or acid aqueous solution to dissolve or soften the scale (chemical reaction), so that it will fall off and be removed. Timely treatment of diesel engine scale is very important for the cooling effect of the engine, otherwise it will affect the heat dissipation quality of the diesel engine.

The cleaning solution formula is: (1) 2.5% concentration of dilute hydrochloric acid or dilute sulfuric acid (special reminder: if you don’t know how to make the formula, please do not use it blindly to avoid damaging the machine water channel); (2) 6% concentration of caustic soda solution; (3) 2-3% concentration of soda ash solution; (4) 10% concentration of acetic acid; (5) 5% concentration of nitric acid.

The first three cleaning fluids are highly corrosive and can be used for corrosion-resistant cast iron parts, while aluminum alloy parts are only suitable for the latter two cleaning fluids. Since there is often grease in the waterway, 2-3% kerosene can also be added to the above cleaning fluids.

Specific steps:

1. Drain the original cooling water of the diesel engine, disassemble the thermostatic valve seat, remove the thermostatic valve, and then inject the special cleaning fluid into the water tank.

Start the diesel engine and run it at medium or low speed for about 10 minutes. Stop and let it stand for 8 to 12 hours to allow the cleaning liquid to fully soak the scale.

2. Start the diesel engine and adjust the throttle position to make the engine speed fluctuate. Use the impact force of water in the cooling system to cause scale to fall off and suspend in the cleaning fluid. Repeat this several times and then stop the engine and release the cleaning fluid immediately.

3. Fill with clean soft water, start the engine, run at low speed for a few minutes and then drain it. This can be repeated 2 to 3 times. After cleaning, drain it again.

4. Add diesel engine coolant or clean soft water. When there is water in the thermostatic valve seat, stop adding, replace the thermostatic valve, and then fill the water tank.

Why is there oil in the diesel engine water tank?

① Due to the failure of engine coolant concentration, cavitation and sand holes are produced in the cylinder liner. Under the action of cylinder compressed gas, the engine oil is blown into the cooling system.

② The compressed gas in the cylinder penetrates the water channel of the cylinder gasket, and the engine oil enters the cooling system and the water tank

③ The cooling copper sleeve of the fuel injector is loose, and the compressed gas in the cylinder blows the engine oil along the copper sleeve into the cooling system and flows to the water tank port.

④ Sand holes and cracks in the oil heater allow the oil to enter the cooling system.

⑤Aging and cracking of the water-blocking ring of the cylinder liner will also cause the oil to enter the cooling system, leaving oil stains in the water tank.

⑥ The expansion water plug of the cylinder head is corroded and the engine oil will seep into the cooling system.

Does the diesel engine water tank need to be added after opening?

First of all, you need to see what kind of diesel engine it is, whether it is a boiling type or a circulating type. For a boiling type, slowly add water until it is full. For a circulating type, do not turn off the engine first, wait for a while, cover the water tank cap with a towel or rag to ensure that the steam does not burn your hands, slowly unscrew the cap, and then add water.

Then remember to find out what caused the high temperature.