What is the pressure in the engine cooling system?

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:42

During operation, the internal combustion engine heats up to a high temperature. The engine cooling system must cope with the function of heat removal. This is necessary for the efficient operation of the power unit. If there is no coolant circulation, then the internal combustion engine will overheat very quickly with all the ensuing consequences. Let's talk about what should be the pressure in the cooling system and how to fix typical problems on your own.

Briefly about the main things

First of all, you need to decide why pressure is in the cooling system. It would seem that the banal circulation of the coolant should be enough to remove heat. It used to be like that when water was poured into the radiator. But it was also normal to meet a car on the side of the road with steam coming out from under the hood. This happened because the waterhad time to cool, and since its boiling point is 100 degrees, it boiled very quickly.

Modern antifreezes, most of which are alcohol-based, boil at about 115 degrees Celsius. But it is worth remembering a school physics course, from where you can find out that an increase in pressure leads to a shift in the boiling point of a liquid. This also applies to antifreeze that circulates through ICE systems.

What is the normal pressure in the engine cooling system?

Here a lot depends on the design features of the car. But usually it is 1, 2-1, 4 atm. for cars. For example, on the VAZ-2110, 1.2 atmospheres can be considered a normal indicator. The critical pressure in the system is reached when the antifreeze is heated and reaches its boiling point. At this time, the pressure in the system must be relieved. This is done in order not to break the radiator or any other weakest point.

The expansion tank cap is responsible for relieving pressure. Its device is extremely simple. There is a metal case with two holes. Inside there is a ball larger in diameter than the holes. When it reaches a certain temperature, it rises. This causes air to be released into the atmosphere. On many cars 1.5 atm. is the pressure at which the reset occurs.

Check valve performance

Until the antifreeze is hot, the ball inside the lid closes the bottom hole while the top one stays open. This is necessary for the flow of air from the atmosphere and the rapid heating of the coolant. I would like to note that it is periodically necessary to check the operability of the cover. After all, it often happens that she wedges in one of the positions. Because of this, the engine either warms up for a long time or does not hold pressure.

Checking the cover of the expansion tank VAZ-2110 is extremely simple. To do this, just unscrew it and shake it. If you hear the ball dangling inside the case, then the system is working and it is not jammed. Excessive pressure in the engine cooling system, as noted above, can lead to fatal consequences. Therefore, on modern cars, the cover has two valves: inlet and outlet. Now on sale you can find covers that work at a certain pressure. But it is strongly not recommended to change the parameters set by the manufacturer.

High blood pressure and methods of struggle

The cooling system is designed in such a way that it is the cap of the expansion tank that is responsible for the pressure in it. Although there are various design options. For example, on some American cars, the expansion tank acts as a sump, and the cap itself is installed on the radiator tee. However, the essence of the work remains the same.

The pressure in the cooling system of the VAZ-2110 engine should be in the range from 1.2 to 1.5 atm., while a drop or excess of these indicators can already be considered a serious deviation. Oftenmotorists are faced with increased pressure. The reason will be the same cover, the valve of which is stuck in the closed position. In this case, the system will warm up, the pressure will increase, and it will not be released. Because of this, vapor-air plugs are formed that prevent the normal circulation of the coolant through the system.

Replacing a failed node

A cooling system cover can last longer than a car engine, or you can buy a new one that will be defective. It's hard to guess here. But in any case, do not try to repair it. It costs a penny for most models and is non-repairable. In the event of a malfunction, it is simply replaced with a new one.

In this case, it is strongly not recommended to shorten the springs by changing the moment of actuation of the cover. After all, many motorists do this, which in most cases does not lead to anything good. Of course, if you have tuned the cooling system and the engine, then it is quite possible that you need to achieve more pressure in the system or, conversely, less. In other cases, it is worth buying only the original or a worthy analogue with the same parameters. Remember that high pressure in the engine cooling system can lead to local overheating of the internal combustion engine and failure of certain components.

System leakage

An even more popular problem among motorists is the lack of pressure. This can happen because of:

• stuck air valve;
• leaksin the cooling system.

Accordingly, identifying the problem is not difficult. The first step is to look at the level of antifreeze on a cold engine. If it does not change from trip to trip, then there are no leaks in the system. The second point is to change the air valve to a new one. After that, the pressure should normalize, and the antifreeze will not overheat. Very often, the increased pressure in the engine cooling system leads to the fact that it then drops. This is due to a partially wedged valve. He either works or he doesn't. As a result, pressure is built up, which can cause a leak in a weak spot, and then leak tightness.

How to find a leak?

To begin with, it is worth starting with a visual inspection. It is worth looking under the car, it is likely that there is a puddle of antifreeze under it. But even here you need to understand that often a gap appears only when a certain pressure is reached, so it will not be possible to find it on a cold one. However, there are special devices for pressurizing the system, while the engine must be cold to avoid burns.

As such a device, you can use a conventional pump and pressure gauge. Everything can be done in a garage. First of all, we disconnect the upper pipe, suitable for the expansion tank. It is advisable to insert a bolt of suitable diameter into the hole. Next, we connect a pump with a pressure gauge to the nozzle and build up pressure. Upon reaching 1.5 atm. the air valve should work. At the same time, we are looking forleak.

The nuances of the cooling system

Much also depends on the coolant used. For example, you don’t even need to pour water into old cars, it’s better to buy inexpensive antifreeze, there will be fewer problems. Nevertheless, modern motors require high-quality cooling. The manufacturer in the manual indicates the recommended grades of coolant. It is advisable to follow these tips and do not dilute antifreeze if you do not have a concentrate.

Modern coolants have different service lives and boiling points. For example, G12 boils later than G11, and G12 ++ has an increased resource, but it also costs more. In any case, in order to avoid boiling the engine, it is recommended to fill in only high-quality coolant.

Genuine Parts

Very often high pressure in the engine cooling system is formed due to a malfunction of the air valve, we have already de alt with this. Another thing is that this valve has an insufficient resource, or even a new one may be inoperative. This also applies to other elements of the cooling system, such as a thermostat, water pump, pipes, sensors, radiators, etc. To sleep peacefully, it is better to get an original, whose service life is often quite long. Of course, such spare parts are many times more expensive, but they almost 100% guarantee the correct operation of the unit as a whole. After all, the failure of such an insignificant element as a cover can lead to a major overhaul of the engine.

As for Chinese components, it's a lottery. Some of them can be quite high quality, while others do not go even 100 kilometers. It's better not to take risks, because the miser pays twice.

Serious Consequences

We have already considered that pressure is created in the engine cooling system. It's quite normal. Another thing is that very often there is a malfunction that is extremely difficult to determine. For example, antifreeze leaves, but there is no visible leak. In this case, it is quite possible for coolant to enter the crankcase. It is recommended to check the oil level regularly. If the coolant really goes into the engine, then the level will rise. Most likely, this indicates a broken cylinder head gasket, changing which is tantamount to overhauling the power unit.

Any part has its own specific resource, upon reaching which there is no guarantee that it will work properly in the future. It is not uncommon for even a new expansion tank cap to be inoperative. And now we are not talking about Chinese parts, but about the original. Unfortunately, there is no escape from this.

Summarize

So we figured out why the pressure in the engine cooling system, why it can be excessively high or, conversely, low. There is often nothing complicated in self-checking, although a lot depends on the car. For example, it happens that the coolant temperature sensor fails. It can give incorrect data to the control devices, thereby introducing the driver intodelusion. It can show both a high temperature of the power unit, and, conversely, a low one. But this will not mean that the system is not working properly.

Any breakdowns in the cooling system must be fixed as soon as possible. It is advisable not to operate the vehicle with a stuck cover or thermostat. Indeed, for some engines, overheating is fatal, and overhaul is quite expensive. In general, it is worth regularly checking the coolant level in the system, making sure that there are no leaks or other defects. It is also recommended to periodically clean the radiators of dirt, as this can cause an increase in engine temperature.