Expansion tank in a car cooling system
Even a short trip by car will be impossible if the car's cooling circuits are faulty. Modern vehicles are driven by thrust generated by combustion processes. The gas-fuel mixture, entering the engine combustion chamber, disintegrates, imparting part of the released energy to the engine's CPG. Normal operation of the system is impossible if all the conditions required for uniform and stable combustion of fuel are not met.
The automotive cooling system maintains the temperature required for engine operation. Most modern vehicles are characterized by the presence of 2 types of internal combustion engine cooling - air and liquid. The engine is cooled with air thanks to the operation of fans, and the operation of liquid cooling is supported by the circulation of the cooler in the radiator circuit. The coolant enters the internal combustion engine and picks up some of the heat during the heating process, and then exits into the expansion tank, from where it is sent to the radiators for cooling.
Expansion tank device
Tank structure
It is made from stamped metal half-forms, which are connected to each other by rolling. There is a neck on the bottom side of the body; it is on its side that the tank is connected to the heating system. On the upper side there is a nipple through which air is pumped into the diaphragm located inside the housing.
A special cover is installed in the upper part of the housing on a bolted connection. It is only necessary in one case, if you need to inspect the tank or replace the diaphragm.
How does the tank work? Expanding water enters the tank through the neck and occupies the space between the walls of the housing and the walls of the inflated diaphragm. The air in the diaphragm is compressed and its size decreases. As soon as the coolant begins to cool, the diaphragm returns to its original volume, squeezing the coolant out of the expansion tank. As you can see, everything is quite simple.
Damage to the expansion tank
A car's expansion tank is usually made of off-white or black plastic. Its shape and dimensions can vary markedly depending on the make and model of the vehicle in which it is installed. There are designs of expansion tanks made of aluminum alloy, intended for tuning the engine compartment. Standard tanks have two coolant outlets and a coolant refill hole with a cap.
The technical characteristics of the cooling circuit capacity determine typical problems that may arise during the operation of automotive expansion tanks:
- Broken cooling circuit hoses.
- The inlet cover is broken.
- Destruction of the plastic case.
All three risk factors are associated with the physical impact of the coolant on the expansion tank chamber.
An aqueous solution of alcohol containing a complex of additional additives is used as a coolant. Additives ensure the most efficient heat transfer and minimize the destructive effect of the coolant on the engine. Russian retail chains of automotive chemicals will offer customers 2 types of coolant - antifreeze and antifreeze.
Antifreeze is a domestic development, differing in the types of additives and price. Antifreeze costs several times more and can provide more effective protection of the internal combustion engine from wear.
The coolant entering the expansion tank often has a fairly high temperature, and in some cases it can boil right in the plastic container. Boiling of the coolant in the expansion tank often leads to its deformation. It also happens that under the influence of heated antifreeze, the tank bursts, the cooler hoses break, or the lid of the tank is knocked out. To prevent such situations, special valve cover designs have been developed.
Let's start replacing - what to pay attention to?
To install the tank you will need screwdrivers, pliers, new clamps, a set of wrenches and sandpaper. Sandpaper is necessary for processing the inlet holes on the plastic of the tank, which have a rough surface. It is necessary to make it smooth, this contributes to a better fit of the system pipes.
Replacement of the tank must be carried out according to the instructions specified in its new kit. If the car has been running, you need to wait until it cools down. First of all, open the car radiator cap, this will reduce the pressure in the system. You can completely get rid of the coolant by unscrewing the cap at the bottom of the radiator. If you recently changed the fluid, then when removing the old tank you need to clamp its pipes to prevent unnecessary losses.
This is followed by installing a new tank and connecting all pipes to it. The clamps must be clamped without using much force so as not to break the inlet holes of the tank. If necessary, add coolant. In a VAZ 2110 car, it is very important to constantly maintain the average fluid level. After completing all the work and checking the remaining pipes of the system, start the car and let it run until it boils. When the fan on the radiator turns on, watch the reservoir cap - it should release pressure.
Valve cover and expansion tank sensors
Valve covers of expansion tanks are a composite mechanism of several plates, springs, locking and connecting parts. Valve cover design may vary depending on the make and model of the vehicle. Despite all the model differences, the design of any valve is extremely simple, and even a child can figure it out.
The valve cover performs the function of relieving excess pressure to protect the expansion tank body from deformation and rupture. When the pressure created by the boiling coolant inside the expansion tank reaches a critical level, then the valve on the cap opens and the excess coolant volume is released into the engine compartment. If the vehicle engine often “boils,” it is worth checking the coolant level in the system.
The fact that repair of the expansion tank cap is necessary may be indicated by frequent “boiling” of the car or the appearance of coolant stains where the vehicle is parked. The reasons for the malfunction of the cover can be very different - from metal fatigue in the design of the valve mechanism to soldering of valve parts to each other. To check its operation you will need a pressure gauge and a car pump. They must be connected to the expansion tank instead of hoses. A working cap will not allow the pressure in the tank to rise above the permissible limit.
Frequent bleeding of excess pressure in the expansion tank leads to a shortage of process fluid in the cooling system. The result of a lack of coolant in the system is regular “boiling” of the internal combustion engine and the inability to fully use the vehicle. The lack of antifreeze in the expansion tank should be indicated by the on-board computer or lights on the car’s dashboard. They read data from the float sensor in the expansion tank chamber.
How to install
There are no significant restrictions affecting the installation location of the expansion tank in the system. Nevertheless, it is advisable to carry out the installation at any convenient point in the return line of the existing heating system.
The reason is that the coolant there is cooler. And this allows you to significantly extend the life of the expansion tank and its membrane.
In addition, if you install the tank near a solid fuel boiler, then in certain situations steam may enter the coolant chamber. As a result, the container will lose the ability to compensate for the expansion of the coolant.
Installation of the tank can be done in two ways. These include installation:
But it should be understood that the first option is intended only for cases where the expansion tank has a moderate volume.
You should not skimp on connecting the tank to the heating system.
So this procedure should be performed using:
- a shut-off valve with a so-called “American” - this design element will allow you to quickly remove the tank from service and, if necessary, replace it, without waiting for the coolant to cool down;
- a tee with a drain tap, which will allow you to quickly empty it before replacing the tank;
- pressure gauge for measuring pressure;
- safety valve or nipple to regulate the pressure inside the equipment.
After installing the tank, it must be configured correctly, taking into account the manufacturer’s recommendations given in the instructions for the purchased equipment. So that the pressure in the tank is appropriate, i.e. less than in the system, which will allow the membrane to deform when the coolant heats up.
If the calculations were carried out incorrectly and the heating system contains a tank of a smaller volume than required, then it will not cope with its duties, but the error can be corrected.
Why do you need to purchase and install a second container in the system? The capacity of which is the difference between the required volume and that available in the tank operating in the system. This method will reduce financial losses.
Repair, replacement and modernization of the expansion tank
The coolant level sensor is part of the design of most expansion tanks. This is the only part of the expansion tank housing that can be repaired. In fact, all repairs to the expansion tank come down to repairing the coolant level sensor or replacing it. Any motorist who has repaired something on their car at least once in their life can change it.
Modernizing the expansion tank involves installing a modern valve cover if the design of the current one cannot perform the function of relieving pressure. If the cap was replaced due to antifreeze leaks, and after installing a new or repaired cap, the leaks did not stop, then the tank will have to be replaced. The procedure is simple and universal - replacing the expansion tank of a VAZ is not much different from replacing the tank on a foreign car.
In order to change the tank, just follow 4 steps:
- Disconnect the cooling system hoses.
- Unscrew the mounting screws, if any.
- Remove the old reservoir from the engine compartment.
- Install the new expansion tank in place of the old one, securing it with screws and connecting the hoses.
The cost of the tank is low, but can vary significantly depending on the store. It often turns out that purchasing auto parts at an auto repair shop is much cheaper than buying it at a shopping center. It would be advisable to turn to the help of a vehicle service and repair center if you don’t have the time to independently search for a tank in nearby stores, and you don’t have the desire to install it. The car service aggregator Uremont.com will help you find the nearest car service center that has the necessary parts in stock.
What to choose?
If you still need to replace the tank, you first need to choose what exactly you will replace the old tank with.
Today there are several decent options on the market that are perfect for your VAZ 2110.
| Option | Peculiarities |
| Standard tank for "ten" | Factory version, which is optimal in terms of price and quality. Sometimes you can’t think of anything better than native parts |
| Foreign analogues | If you can find the perfect tank, you're in luck. The quality is up to par and it performs its functions perfectly. But finding such an option is extremely difficult. Plus the price is higher |
| Capacity from Priora | Many consider it an ideal choice for the VAZ 2110. It costs about 300 rubles. You can find it by catalog number 2170-1300060. The walls are thicker, which has a positive effect on reliability. Just keep in mind that there are two types:
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If you choose to replace the tank from Priora, then you should take the version for a car without air conditioning.
