Does your car need constant attention? It is not surprising, because the car, from which you expect long work and service faithfully, should be systematically checked for any, even the slightest problems, eliminating them in time and solving problems. When we mention the reliability, uptime and power of a car, we cannot fail to mention its heart - the power unit.
The car engine is constantly exposed to various loads. Changes in the temperature regime are also not left without attention. Prolonged exposure to various climatic conditions usually causes the radiator tank to leak and damage your car's engine.
So that the frequent replacement of the engine does not hang over you as a heavy burden, you should constantly monitor the temperature regime of the antifreeze and, as a result, the motor itself. The cooling system of the car is responsible for this. Modern vehicles are equipped with an intelligent cooling system that allows not only to regulate the temperature of the power unit, but also to protect the radiator metal from corrosion due to lubricants. It also provides a constant circular run of antifreeze, thanks to its antifreeze properties.
A very important step is the selection of a suitable high-quality cooling element for your "favorite", because this will directly affect the operational life of some of the main elements that are included in. If at least one of the parts fails, this entails serial "kills" of other elements. The first, most likely, this will be the engine radiator, thermostat, expansion tank, pump, fan and radiator cap.
First of all, let's turn to the cooling radiator of the power unit. We think it would be superfluous to talk about the importance of this detail for a long time. Its work is carried out due to a special fan and an oncoming air flow. This system is quite complicated, but often the reason for the failure of the entire radiator lies only in the fact that the radiator cap has any defects and malfunctions.
At first glance, it seems to be a trifling element, but in fact it is very important! The cap holds the high-pressure antifreeze inside the radiator that cools the engine. Experts strongly recommend not to save money and in the event of a radiator replacement, be sure to purchase a new plug. In addition, its cost is relatively low. This will strengthen your confidence in the condition of the cooling system. Otherwise, after the power unit cooling radiator, you will have to replace another element.
In the event that the failure of the radiator did not occur due to physical impact or deformation, but its manifestation is expressed, for example, in a leak in the expansion tank, it is possible that it was the radiator cap that caused the failure.
It is clear that by replacing the radiator and installing the old plug, you will get an identical result. Therefore, the purchase of a new cover is absolutely good advice for car owners.
How does a radiator cap affect cooling?
The job of the radiator cap is to maintain excess pressure in the system. With its help, excess antifreeze is etched, expanding from heating. It has two valves. The first is designed to maintain pressure and opens if it is exceeded. The second begins to act when the pressure drops below atmospheric. The termination of the first valve consists in its permanently open position or opening at a pressure exceeding the norm. Also, the lid may not fit snugly against the neck, which in this case lets air in, leading to the likely boiling of antifreeze.
How to check the radiator cap?
The cooling system of a car is a very important part of the whole car. In order to avoid damage to the internal combustion engine from overheating, problems with the radiator should be identified and solved in a timely manner. And the very first thing you should be puzzled with is how to check the radiator cap.
1.
First of all, carefully inspect the cover for any mechanical damage. If it has cracks, rust, corrosion, scratches and other signs of wear, then it should be replaced with a new one.
2. The radiator cap acts as a kind of barrier that holds. The design of the cork is designed in such a way that a special spring is built into it to contain strong pressure. So, the next step involves checking this spring. Check to see how hard it compresses. If light pressure is enough, then the use of such a cover is strictly prohibited.
3. Next, check the vacuum valve, pull and open it. Then release and make sure that it closes completely. Also check the vacuum valve seat for dirt deposits that may prevent it from performing its function correctly. If deviations from the norm are observed, then the radiator cap must be replaced.
4. Then, using a special device, check the pressure of the radiator cap. Take the pump and attach it to the cap following the instructions.
Wait for the valve to open by driving the pump while the valve opens. Increase the pressure until the gauge needle stops. Check your results with the ones below. The pressure at which the inlet valve opens should be 107.8 ± 14.8 kPa, and opens at 83.4 kPa. If these values \u200b\u200bare not the same for you, then it's time to change the radiator cap.
When inspecting the radiator, you need to be as serious and focused as possible. If a replacement is required, approach the choice of even such a seemingly trifle as a radiator cap, seriously, focusing on the marking of a worn element.
A radiator cap should be purchased if, during a visual inspection, you notice the following:
- scratches, cracks, rust and other signs of wear of the radiator cap appeared on the cover;
If the spring compresses easily;
Leaky closing vacuum valve;
Vacuum valve seat dirty;
There is a leak of antifreeze in some places.
Replacing the radiator cap should not be accompanied by doubts, as well as excessive savings. Compare the cost of a cap and a radiator or even an entire engine. True, an incommensurable ratio? It immediately becomes clear that the timely purchase of a radiator cap will protect you from further spending much more money.
Please also note that the choice of radiator cap should be made in such a way that it fits your car. The marking of the standard cover will help in the choice.
The very reasonable cost of the radiator cap will not entail large financial costs. But you will be sure that the automotive cooling system is reliable and works correctly. If you ignore all the above tips and guidelines, then you cannot avoid in the near future, at least replacing the radiator, and to the maximum, the entire power unit!
This question is asked by motorists at different times of the year. After all, the work of the radiator cap provides increased pressure in the engine cooling system, which, in turn, makes it possible for the engine to work normally and the interior stove to function in the cold season. Therefore, its condition must be monitored regularly, and if necessary, it is necessary to change the valve, the sealing ring, or the entire cover, since most often it is not a collapsible structure. Therefore, to check how the lid works, one visual inspection is not enough, you also need a test and pressure.
How does a radiator cap work
In order to better understand the essence of checking the radiator cap, first you need to discuss its structure and circuit. First of all, it should be noted that the antifreeze in the cooling system is under high pressure. This circumstance is done specifically in order to increase the boiling point of the coolant, since the operating temperature of the engine is slightly higher than the traditional +100 degrees Celsius. Typically, the boiling point of antifreeze is around + 120 ° C. However, it depends, firstly, on the pressure inside the system, and secondly, on the state of the coolant (as the antifreeze ages, its boiling point also decreases).
Through the radiator cap, not only antifreeze is poured directly into the radiator housing (although usually of the corresponding system), but the coolant converted into vapor also enters the expansion tank through it. The device of the car radiator cap is quite simple. Its design involves the use of two gaskets and two valves - bypass (another name is steam) and atmospheric (another name is inlet).
The bypass valve is located on a spring-loaded plunger. Its task is to smoothly control the pressure inside the cooling system. Usually it is about 88 kPa (it differs for different cars, and also depends on the engine operating conditions for a particular engine). The task of the atmospheric valve is the opposite. So, it is designed to provide a gradual equalization of atmospheric pressure and increased pressure inside the cooling system in a situation where the engine is turned off and cools down. The use of an atmospheric valve provides two aspects:
- A sharp jump in the temperature of the coolant at the moment the pump stops is excluded. That is, heat stroke is excluded.
- The pressure drop in the system is eliminated at a time when the temperature of the coolant gradually decreases.
Thus, the listed factors are the answer to the question, what affects the radiator cap. In fact, a partial failure of it usually leads to the fact that the boiling point of antifreeze decreases, and this can lead to its boiling during engine operation, that is, engine overheating, which in itself is very dangerous!
Symptoms of a failed radiator cap
The car owner is advised to periodically check the condition of the radiator cap, especially if the car is not new, average or below this, and / or if water or antifreeze diluted with it was used as a coolant. It also makes sense to check the condition of the cover when antifreeze is used in the cooling system for a very long time without replacing it. In this case, it may begin to corrode the rubber seal on the inside of the cover. A similar situation can arise, for example, when oil can get into the coolant. This process fluid is detrimental to the cap seal, and it also degrades the performance of the antifreeze.
The main symptom of a breakdown in this case is a leak from under the radiator cap. And the stronger it is, the worse the situation, although even with the slightest leakage of liquid, it is necessary to perform additional diagnostics, repair or replace the cover.
There are several other indirect signs that the radiator cap is not holding pressure in the cooling system. These include:
- the bypass valve plunger sticks (usually skewed) during the return movement for compression;
- weakening of the cover spring;
- when the atmospheric valve is pulled out of its seat (seat), it sticks and / or does not fully return to it;
- the diameter of the valve gasket is larger than the diameter of its seat;
- cracking (erosion) of rubber gaskets on the inner surface of the radiator cap.
The listed malfunctions can cause the radiator cap to let coolant out (). There are a couple more indirect signs of failure of the cover. However, they can also indicate other, more serious, breakdowns in the cooling system. Yes, they include:
- when the bypass valve is stuck, the upper radiator pipe swells;
- when the atmospheric valve is stuck, the upper radiator hose retracts.
Even if one or the other valve does not work properly, the coolant level in the expansion tank will be the same. Under normal conditions, it should change (albeit slightly) depending on the temperature of the engine.
How to check the operation of the radiator cap
You can check the health of the radiator cap in several ways. To do this, follow the algorithm below.
It is necessary to check the radiator cap with the engine completely cold, as the part will have a high coolant temperature. If you touch it when it is hot, you can burn yourself! In addition, hot antifreeze is in the system under pressure. Therefore, when the lid is opened, it can splash out, which also threatens with serious burns!
- visual inspection. First of all, you need to visually check the condition of the cover. Ideally, it should not have mechanical damage, chips, dents, scratches, and so on. If these damages occur, then sooner or later a corrosion center will appear in their place, which will constantly expand. Such a cover can either be cleaned and repainted, or replaced with a new one. The second option is preferable.
- Spring check. The design of each radiator cap includes a spring that serves as part of the safety valve. To check, you need to squeeze it with your fingers. If it is squeezed very easily, it means that it is unusable and needs to be replaced (in case the lid is collapsible). However, most often the covers are non-separable, so it must be completely replaced.
- Atmospheric valve check. To check it, you need to pull it and open it. Then release and check that it closes completely. Also, during the inspection process, it is imperative to check the valve seat for the presence of dirt or deposits in it, which may appear during the evaporation of the old antifreeze. If there is dirt or deposits, then there are two options. The first is to try to clean the saddle. The second is to replace the cover with a new one. However, everything depends on the degree of contamination of the inner surface of the vacuum valve.
- Check valve actuation. To do this, you need to use a special device. About him a little further.
There is a so-called "folk" method for checking the condition of the radiator cap. It consists in the fact that on a warm (switched on) engine, feel the radiator pipe. If there is pressure in it, then the cover is holding, and if the pipe is soft, then the valve on it is leaking.
However, there is also a description of another "folk" method, which is actually incorrect. So, it is argued that it is necessary to squeeze the upper pipe by hand, while at the same time observing an increase in the liquid level in the expansion tank. Or, similarly, by dismantling the end of the outlet pipe, observe how the antifreeze will flow out of it. The fact is that the liquid column lifts the valve seat only in a situation where the pressure from the compression force will be much greater. In fact, as the pressure increases, the liquid presses in all directions, and will only lift the bypass valve “in excess”. And the pressure of the coolant is distributed through all channels, and not just in one particular one (to the seat).
Checking the lid with improvised means
Checking the operation of the bypass valve is quite simple. To do this, you need to disconnect any small pipe of the cooling system on the engine, for example, a damper or manifold heating. Next, you need to use a compressor with a pressure gauge (to know the exact supply pressure), you need to supply air to the system. The pressure value at which the valve operates will be easily determined by the hissing and gurgling coming from the elements of the cooling system. Please note that at the end of the procedure, the pressure cannot be abruptly released. This threatens that when the lid is opened, the antifreeze may splash out under pressure. Under normal conditions, the atmospheric valve is designed to prevent this.
From the expansion tank, the liquid enters the radiator through the check valve. It retains pressure from the radiator side, but quietly opens if there is a complete vacuum there. It is checked in two stages:
- You need to try to lift the valve patch with your finger. Ideally, it should move with minimal effort (no mechanical resistance).
- On a cold engine, when there is no excess pressure in the radiator, it is necessary to install a plug in its seat. Next, disconnect the tube going to the expansion tank of the cooling system and try to “inflate” the radiator through it. The valve is designed for low pressure, so you will probably be able to blow a small amount of excess air into the radiator. This can be checked by unscrewing the radiator cap again. In this case, a characteristic hissing sound of air emanating from it should be heard. Instead of a mouth, a compressor with a pressure gauge can also be used. However, you need to make sure that the pressure does not rise sharply.
Cover Gasket Check
Together with the valves, it makes sense to check the tightness of the upper gasket of the radiator cap. Even when air whistles out when the lid is opened, this only indicates that the valve is working. However, through a leaky gasket, antifreeze can gradually evaporate, due to which its level in the system drops. In this case, the reverse process also occurs, when instead of taking the antifreeze from the expansion tank, air from the atmosphere enters the system. This is how an air lock is formed (“airing” the system).
You can check the plug in parallel with checking the check valve. In its original position, it must be installed in its place on the radiator. To check, you need to “inflate” the radiator through the tube coming from the expansion tank (however, the pressure should be small, about 1.1 bar), and close the tube. You can just listen to the hiss of the outgoing air. However, it is better to make a soapy solution (foam), and coat the cork with it around the perimeter (in the area of \u200b\u200bthe gasket). If air comes out from under it, it means that the gasket is leaky and needs to be replaced.
Radiator cap tester
Many car owners who are faced with a depressurization of the cooling system are interested in the question of how to check the performance of the radiator cap using special testers. Such a factory device costs more than 15 thousand rubles (as of the beginning of 2019), so it will be available only for car services and craftsmen who repair cars on an ongoing basis. Ordinary car owners can make a similar device from the following components:
- A bad radiator from any old car. Its general condition is unimportant, the main thing is that it has a whole top tank. Especially the part where the cork is attached directly.
- Sandpaper and "cold welding".
- Nipple from the car camera.
- Compressor with accurate pressure gauge.
Omitting the details of the manufacture of the device, we can say that it is a cut off upper radiator tank, on which all the honeycombs were drowned out so that air would not escape through them, as well as side walls with a similar purpose. The nipple of the automobile chamber is hermetically attached to one of the side walls, to which the compressor is connected. Next, the test cover is installed in its seat, and pressure is applied using a compressor. According to the readings of the pressure gauge, one can judge its tightness, as well as the performance of the valves built into it. The advantage of this device is its low cost. Disadvantages - the complexity of manufacturing and non-universality. That is, if the cover differs in diameter or thread, then a similar device must be made for it, but from another unusable radiator.
With a radiator cap tester, you can check their operating pressure range. It will be different for different engines. In particular:
- Gas engine. The opening pressure value of the main valve is 83…110 kPa. The opening pressure value of the vacuum valve is -7 kPa.
- Diesel engine. The opening pressure value of the main valve is 107.9±14.7 kPa. The closing pressure of the vacuum valve is 83.4 kPa.
The given values are averages, but it is quite possible to be guided by them. You can find exact information about the operating pressures of the main and vacuum valves in the manual or on specialized resources on the Internet. In the event that the tested cap shows a pressure value that is very different from the one given, it means that it is faulty and, therefore, requires repair or replacement.
Radiator cap repair
Repairing the radiator cap is often impossible. More precisely, the result will most likely be negative. So, you can independently try to replace the rubber gaskets on the lid, clean the rust on its body, and repaint it. However, if the spring has weakened in the design or one of the valves (or two at once) has failed, then their repair is hardly possible, since the body itself is in most cases non-separable. Accordingly, the best solution in this case would be to buy a new radiator cap.
Which radiator cap to put on
Many motorists who have started checking and replacing the said cover are interested in the question of what are the best radiator covers? Before answering this question, you must immediately pay attention to the fact that the new cover must have the same performance characteristics as the one being replaced. In particular, it must have the same diameter, thread pitch, internal valve size, and most importantly, it must be designed for the same pressure.
As a rule, for most modern passenger cars, covers are sold that are designed to operate in the pressure range of 0.9 ... 1.1 bar. However, before buying, you need to further clarify this information, since sometimes there are exceptions. Accordingly, you need to choose a new cover with similar characteristics.
Please note that you can also find so-called tuned radiator caps on sale, designed to work at elevated pressures, in particular, up to 1.3 bar. This is done in order to further increase the boiling point of antifreeze and thereby increase the efficiency of the car engine. Such covers can be used on sports cars, the engines of which are designed to operate at high power, but for a short period of time.
For ordinary cars used in the urban cycle, such covers are categorically not suitable. When installing them, a number of negative factors arise. Among them:
- The work of the elements of the cooling system "for wear". This leads to a decrease in their total resource and the risk of premature failure. And if a pipe or clamp bursts from excessive pressure, this is half the trouble, but such a situation can end much worse, for example, if a radiator or expansion tank bursts. This already threatens costly repairs.
- Reduced antifreeze resource. Any coolant has a certain operating temperature range. Going beyond it reduces the performance of antifreeze and significantly reduces the time of its use. Therefore, when using tuned covers, you will have to change antifreeze more often.
Thus, it is better not to experiment, and follow the recommendations of the manufacturer of your car. As for specific brands of radiator caps, there are quite a lot of them, and they are different for different cars (for European, American, Asian cars). It is best to buy original spare parts. Their article numbers can be found in the documentation or on special resources on the Internet.
Conclusion
Remember that a serviceable radiator cap is the key to the normal operation of the engine of any car with a closed cooling system. Therefore, it makes sense to check its condition not only when it failed (or problems began in the operation of the cooling system), but also periodically. This is especially true for older machines, and/or machines that use water or diluted antifreeze in the cooling system. These compounds eventually damage the cover material, and it fails. And the breakdown of its individual parts threatens to reduce the boiling point of the coolant and overheat the engine.
It is necessary to choose a new cover according to previously known parameters. This applies both to its geometric dimensions (lid diameter, gasket diameter, spring force) and the pressure for which it is designed. This information can be found in the manual or simply buy a radiator cap similar to the one installed before.
The cooling system is an important component of the health of the car. In order to avoid engine damage from overheating, problems with the radiator should be identified and solved in time. And the first thing you should pay attention to is checking the radiator cap.
First you need to carefully examine the appearance of the cover for mechanical damage. Scratches, rust, cracks, corrosion and other signs of wear indicate the need to replace the cover with a new one. The radiator cap serves as a barrier that keeps the coolant in. To hold strong pressure, the design of the cover assumes a spring. The next step is to check the spring. You need to try how hard it compresses. If the spring compresses easily, the use of such a cover is not recommended.
The car needs constant attention. Even the smallest breakdown, such as a leaking radiator cap or a malfunction of the valves in it, can disable large components and assemblies, so it is very important to replace it in time. About what function the car radiator cap performs and what threatens its malfunction can be found in this article.
Why you need a radiator cap
The radiator cap performs not only the role of a barrier that prevents splashing of antifreeze from the expansion tank, as many motorists think. In fact, this is a rather complex device consisting of two valves.
The inlet valve allows antifreeze to enter the tank when the temperature of the car engine changes. If the temperature rises or boils, then the inlet valve does not have the ability to supply enough fluid to the expander. It is completely closed, thereby isolating the expansion tank and the cooling system.
With a further increase in pressure, the exhaust valve is already activated, some of the volume of the coolant enters the expansion tank, thereby relieving pressure. If the pressure is not relieved in time, then the cooling system will simply break in one of its weakest points. As a rule, these are the junctions of the nozzles. In addition, overheating of the engine caused by a malfunctioning radiator cap can lead to serious deformation of its constituent elements, such as the cylinder head, and subsequent failure of the entire unit.
How to check the radiator cap
If it is already leaking from under the cover, then there is no point in checking it. However, it is better to prevent such a situation by preventing leakage, and replace the cover in time. This can be done with periodic inspections.
In order to check the health of the radiator cap, it must first be removed and carefully inspected. The main visual signs that it is time to change the cover:
- deep scratches;
- the presence of rust;
- deformation;
- cracks that break the tightness.
In addition, it is necessary to check the stroke of the cover spring. If you can squeeze it without much effort, then the cover must be replaced.
Checking the operation of the valve system is best entrusted to car service specialists. If the opening moment of the valve does not meet the standards, then the radiator cap must be changed.
How to replace the radiator cap
In order to replace the radiator cap, you must first purchase it. Since this element of the engine cooling system is quite important, you should not save money by buying low-quality cheap products from unknown manufacturers. First of all, we can note such firms as TAMA and MASUMA. The covers of these manufacturers are distinguished by good performance, reliability and at the same time low price. They have to be changed relatively rarely, no more than every 50 thousand kilometers. In order not to forget, you can combine this process with the replacement of brake pads, while the frequency will be approximately the same.
Before going to the store, you should know which radiator cap is installed on your car. There may be differences in the method of attachment and size for different brands of cars. You can take the old cap with you to the store as a sample.
| Manufacturer | vendor code | Name |
|---|---|---|
| MASUMA | MOX200 | Radiator cap 1.1KG/CM2 |
| MASUMA | MOX201 | Radiator cap 0.9KG/CM |
| MASUMA | MOX202 | Radiator cap 1.1KG/CM2 |
| MASUMA | MOX203 | Radiator cap 0.9KG/CM |
| MASUMA | MOX204 | Radiator cap 0.9KG/CM2 |
| MASUMA | MOX205 | Radiator cap |
| MASUMA | MOX208 | Radiator cap 1.05KG/CM2 - FUT-R142 |
| MASUMA | MOX210 | Radiator cap (R183) 1.0KG/CM2 |
Replacing the cover is fairly easy. It is easily unscrewed by hand, and a new one is put in its place. The main thing is to do this with a cold engine, otherwise you can get burned. The lid should be screwed in thoroughly, avoiding possible spontaneous unscrewing due to vibration.
If you need to purchase a new high-quality radiator cap, it can be done in any of the IXORA stores, as well as in our online store. On sale are both the already mentioned TAMA and MASUMA lids, as well as products from other manufacturers, but also of the highest quality. Consultants will help you with the choice of the goods which are ideally suited especially to your car.
