We checked 10 expansion tank caps installed on all VAZ cars except Vesta, XRAY, Largus and “classics”. Samples were purchased all over Russia using a remote order.
Triune task
The expansion vessel plug prevents the liquid from splashing up and becoming contaminated. It also maintains an increased pressure in the system when the fluid expands due to heating. And the plug, when the system cools, must allow air to enter the expansion tank, so as not to create a vacuum, which leads to compression of the hoses.
An ordinary plug would handle the first task, but two valves serve to maintain high pressure and prevent vacuum. The exhaust valve controls the overpressure in the system and should open at 1.1 bar. The inlet valve opens when the pressure in the system falls 0.03-0.13 bar below atmospheric pressure.
Plug elements: 1 – valve holder; 2 – inlet valve; 3 – spring inlet valve; 4 – exhaust valve seal; 5 – exhaust valve; 6 – exhaust valve spring; 7 – body wrap; 8 – cover body.
Methodology
All plugs were checked for compliance with geometric dimensions by screwing them onto the threaded neck of a standard expansion vessel used on VAZ vehicles. Then the values of pressure and vacuum were measured, with the exhaust and inlet valves working.
Thereafter, the samples were subjected to “drying”. We call this placing lids in a thermal chamber at 125°C for 24 hours. After that, the covers withstood the entire test cycle again.
Checking the outlet valve opening pressure on the stand. The pressure in the tank is more than 2 bar, but the cork does not open. SchA will explode!
Members
AROKI 332080, Dimitrovgrad
estimated price 130 The cork does not hold any pressure at all, which is why the motor can boil under a light load. Total failure. |
Auto Tech AT 1065-001 CR
estimated price 260 Initially, the cork gave satisfactory results in terms of pressure, but after drying it lost the correct geometric dimensions and no longer wrapped around the neck of the tank. failed. |
AVTOVAZ 2108-1311065-004
estimated price 110 The cork withstood the pressure parameters until drying, and after heating, the pressure relief valve began to stick periodically. You can buy if there are no others. |
Automatic device 2108-1311065-01
estimated price 280 The plug is absolutely thermally stable, but does not maintain sufficient pressure in the system. This can cause the engine to boil under load. Cork for the winter? Better to avoid. |
Pramo 21080, China
estimated price 190 It maintains an overpressure in the system of only 0.3 bar, which is unacceptable for modern engines and loads. Not apply! |
HPA 2108–1311065
estimated price 200 This cork won’t do any damage other than the money spent on the purchase. It couldn’t even be screwed onto the neck of the tank. Total failure. |
ED Eurodetal, Rostov-on-Don
estimated price 180 The plug can withstand an overpressure of only 0.1 bar. Engine boiling is inevitable. Do not buy! |
Ganz GRF 10001, China
estimated price 250 It seems that they have decided to make the cork absolutely hermetic. It withstood an overpressure of more than 2 bar. Will the cooling system hold up? But after drying, the cork stopped wrapping around the neck of the tank. Total failure. |
Unnamed
estimated price 190 The cork ensures free communication of the tank with the atmosphere. Such a product makes no sense. Do not buy! |
luzar
estimated price 230 The cork withstood the factory requirements with minor flaws in the “raw” state and returned to normal after drying. You can take! |
The test results relate only to a specific sample of products and cannot serve as a basis for judgments on all products with the same name as a whole.
Results
It was no accident that our reader sounded the alarm: to buy the simplest, it seems, detail is really an issue. Of the dozens of covers we tested, only two can be put on cars, and even those aren’t ideal. A simple device, no microprocessors or advanced technology for you – what is the problem in ensuring quality?
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Alexey Khomyakov, Test Engineer, NPO Talis LLC
SPECIALIST’S COMMENTS– Recently, when testing various auto parts, we get more and more frightening results: the quality of spare parts is rapidly deteriorating! More than half of the presented samples of expansion vessel caps perform the function of plugs, and no pressure is released at all, even if its value exceeds 2 bar.
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Why do we cook?
The operating temperature of engines increases over the years – this is required by the tendency to increase efficiency. The operating temperature of the electric fan on the first injection VAZs was 99 ° C, and on later models it grew to 105 ° C. This is a consequence of environmental regulations – many foreign cars have even higher temperatures.
In this case, the specified temperature is measured where the sensor is located. And in some places the coolant heats up even more. Increase the pressure in the cooling system to prevent it from boiling.
Modern antifreezes boil under atmospheric pressure at temperatures around 108°C. And only by increasing the pressure in the system, it is increased to a minimum of 120-125°C. With a decrease in atmospheric pressure, for example, in the mountains, boiling begins earlier – especially during heavy engine operation: dragging, steep climbs, and so on.
- Why modern engines are doomed to overheat is described here.
- “Behind the wheel” can be read in Telegram.
A reader from Lipetsk turned to the editors of “Behind the Wheel” with a request to test the VAZ caps for the expansion tank of the cooling system – he was tired of changing them!
This cheap detail can kill the engine!
Source: Z R