1.？ Why do you need coolant?
As we all know, when the normal working temperature of the vehicle engine is between 85℃ and 105℃, when the working temperature of the engine continues to rise above 105℃ without cooling control, a lot of white steam will "boil". If the engine is boiled in water, it will cause the engine to overheat, and even lead to serious consequences such as engine scrapping. It can be seen that the cooling system is very important to maintain the healthy working state of the vehicle. The engine cooling system mainly depends on water cooling, and the coolant flows between the engine water channel and the radiator through the pressure of the water pump, taking away excess heat, so that the temperature of the engine is always within the normal range.
It can be seen that the key to engine cooling is coolant. In order to dissipate heat and prevent the engine from "boiling", the boiling point of coolant is required to be high, generally above 105 degrees (the actual boiling point is higher after pressurization).
The second requirement of coolant is antifreeze, which can prevent the coolant from expanding in freezing volume under cold winter conditions, leading to the expansion of radiator and engine cylinder (the freezing volume of liquid will become larger). So the coolant is also called antifreeze, or cooling antifreeze. The freezing point of general antifreeze coolant can reach -40℃, and antifreeze with special requirements can be as low as -60℃.
2.？ There is no coolant. Can I add water?
Although coolant has the advantages of high boiling point and low freezing point, it does not mean that the larger the value, the better the effect. Choose the coolant according to your own environment and habits in the car, so that it can play its best role. For example, in the low temperature area in the north, you can choose a coolant with a low freezing point, and in the high temperature area in the south, you can choose a coolant with a high boiling point. Friends who like to drive fiercely can choose a coolant with a high boiling point.
Some cars mainly ask Bian Xiao. Coolant products on the market are blue, pink and green. How to choose?
Generally speaking, coolant manufacturers are differentiated according to their ingredients, such as propylene glycol is blue coolant, glycerol is pink, and green is ethylene glycol coolant. However, it is necessary to pay attention to the prohibition of mixing, what color of coolant the vehicle itself is, and then add this color of coolant. If the coolant with different composition needs to be replaced, the cooling system needs to be flushed before replacement.
Many old drivers said that there was no coolant before, and our engines were all cooled by water circulation. If there is a lack of coolant, can you add water? In the case of an emergency when the coolant alarms, it is ok to add water temporarily for cooling, and only distilled water can be added. Do not add water for a long time, the coolant will be diluted and the cooling effect will be reduced. Don't add tap water. After the tap water is boiled, calcium and magnesium ions will produce calcium carbonate and other scales, which will damage the functions of engines and other components after long-term deposition.
3.？ How often does the coolant change?
Some car owners said that my car has been driving for 200,000 kilometers and the coolant has not been changed. The engine is running well. Others said that my car coolant was used quickly, and it didn't take long for it to be much less.
For most domestic cars, the annual consumption of coolant is about 15%, but the consumption of each car is different. However, it is worth noting that consumption and replacement are two different concepts. After the coolant is consumed, the same type of product can be added. Replacement requires flushing the cooling system and completely replacing it with a new one, just like refilling a cup and washing it with another drink.
According to Toyota Corolla's maintenance plan, replace 1.6 thousand kilometers for the first time every 40 thousand kilometers, and then every 80 thousand kilometers.
Honda, replaced for the first time in 200,000 km or 10, and replaced every 654.38+10,000 km or 5 years thereafter.
Japanese Mazda, adopting FL22 model, was replaced for the first time in 200,000 km or 10, and then every 65,438+10,000 km or 5 years. The model G30-9 1 was replaced for the first time at 65438+ 10,000 kilometers or 15, and then every two years.
Self-owned brand vehicles have a slightly shorter replacement cycle. Changan CS75 shall be replaced every 20,000 kilometers or 1 year. GAC Chuanqi GS8 is replaced every two years. SAIC Roewe i6 is replaced every 80,000 kilometers or 3 years. Geely Emgrand is replaced every 50,000 kilometers.
(GAC Chuanqi GS8 Maintenance Manual)
Owners who don't know how often to change the coolant should "learn" the maintenance manual and change the antifreeze according to the maintenance manual and the replacement cycle required by the manufacturer, which is the safest.
4.？ Is anhydrous coolant really that magical?
In the 4S shop, have you ever heard of an anhydrous coolant, which has strong heat dissipation ability, high boiling point, and the most important thing is "maintenance-free for life"?
First of all, is it strong in heat dissipation? The main body of ordinary coolant is water, and the specific heat capacity of water is the largest among common substances in nature, reaching 4.2 kJ/(kg c). The main component of anhydrous cooling liquid is propylene glycol, and its specific heat capacity is 2.49 kJ/(kg c). The same water and propylene glycol have the same heat in the same time, and the smaller the specific heat capacity, the faster the temperature rises. For example, under the same condition of 90 degrees, the temperature of water may reach 100 degrees after circulating in the water tank for one week, and propylene glycol may have reached 1 10 degrees. After reading this, do you dare to say that you are good at refrigeration without water?
Second,? Does it have a high boiling point? The boiling point of anhydrous refrigerant can reach 190℃, but high boiling point is not necessarily a good thing. You don't know that the engine has been overheating. If it exceeds 1 10℃ for a long time, the oil will be seriously attenuated, and the deformation in the cylinder will even lead to cylinder pulling.
Third,? Is it really maintenance-free? According to the experience of some netizens after using it, the consumption of anhydrous frozen liquid is extremely fast, and 8 thousand-1.3 thousand kilometers is below the warning line.
Toyota officials have issued a notice to warn people not to replace anhydrous coolant because of flammability, overheating and increased load. Anhydrous coolant is widely used in racing cars, but unlike racing engines, using anhydrous coolant will bring a series of problems.
This article comes from car home, the author of the car manufacturer, and does not represent car home's position.