Exhaust gases in your engine coolant are usually a sign of a blown head gasket or a cracked cylinder head. Continuing to drive your vehicle in any of these cases will quickly lead to complete engine failure. If you suspect that you have any of these problems, you should perform this test immediately. The test kit has been available at most auto parts stores for less than $50 since 2010. Testing for exhaust gases in your coolant will take anyone with basic auto repair knowledge less than 25 minutes to complete.
Tips
- A failed head gasket and cylinder head is often caused by another problem in the vehicle's cooling system, such as a severe blockage in the radiator or something else that is preventing the cooling system from operating at full efficiency. If you find exhaust gases in your coolant, inspect and repair the rest of the cooling system before performing head gasket or cylinder head repairs to ensure that new parts have not failed due to an old problem.
Which gasket material is better?
Gaskets made of different materials
When replacing a gasket, many car owners have a reasonable question: which gasket is better - metal or paronite? Each of these materials has its own advantages and disadvantages. At the same time, you need to understand that if the manufacturer recommends using gaskets made of a certain material, then you must adhere to these requirements.
As a rule, a metal gasket is stronger than its paronite counterpart. Therefore, it is advisable to install it on powerful turbocharged or forced engines. If you do not plan to tune the engine of your car, but simply operate it in a gentle mode, then the choice of material does not matter much to you. Accordingly, a paronite gasket is quite suitable. Moreover, this material is more flexible and is able to adhere more tightly to work surfaces.
Also, when choosing, it is necessary to take into account that the material from which the gasket is made does not have a primary impact on its service life. A much more important indicator is how the gasket was installed. The fact is that there are very thin walls between the individual groups of holes. Therefore, if the gasket is not installed exactly in the seat, then there is a high probability of burnout even in the strongest material.
The most obvious sign that the gasket was installed incorrectly is its rapid failure. Also, if you installed it incorrectly, the car may simply not start. In diesel engines, the knocking of the pistons may also be heard. This happens because the piston touches the edge of the gasket.
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Among various auto systems, the crankcase ventilation system plays a significant role in the formation of the air-fuel mixture, stable and economical operation, full power delivery, protection of engine oil and extension of the life of the cylinder-piston group.
In the design of a car, the crankcase ventilation system is the “lungs” of the engine, necessary for its normal functioning. The system is called PCV (Positive Crankcase Ventilation). However, it is the one that is undeservedly given a minimum of attention and maintenance, and many car owners do not even know about its existence. In this article we will try to understand why this system is needed, how it works, its inherent faults and methods for checking its performance.
What are “crankcase gases”?
During combustion, the fuel-air mixture sharply increases in volume, creating enormous pressure inside the combustion chamber. The expanding gases from combustion force the piston to bottom dead center, causing the engine crankshaft to rotate. Some of the gases penetrate through the leaks between the rings and the cylinder mirror into the oil pan, where, mixing with oil vapor, they create pressure that aggressively affects the crankshaft seals and the pan gasket, and the oil dipstick channel.
The expansion stroke is repeated in each cylinder, constantly pumping the next portion of gases into the sump, and if the crankcase ventilation does not work, the gases will either squeeze out the crankshaft oil seals, or “knock out” the oil dipstick and expel the oil from the crankcase, with all that follows.
In addition, particles of unburned fuel, small fragments of soot, and moisture vapor are transferred to the sump along with the gas, which are mixed with the engine oil located in the engine sump. This, in turn, leads to oxidation of the oil, clogging it with wear products, reducing its performance properties and reducing its service life.
System design
In order to minimize the impact of gas pressure, the engine design provides crankcase ventilation systems. Modern cars use a closed ventilation system, which is necessary to comply with environmental standards.
Crankcase ventilation system design
Despite the differences in systems on different brands of cars, they all have three common components, such as:
• Air pipes for removing gases from the crankcase;
• Ventilation valve, responsible for regulating the gas pressure;
PCV valve
• An oil separator that cuts off oil vapors as gases exit the engine sump.
Oil separator
The valve opens when excess pressure appears and closes when there is a vacuum, that is, the principle of its operation is based on the difference in pressure behind and in front of it.
The separation of oil particles is carried out by the passage of gases through a system of labyrinths, vortices and grids in oil separators. The separated oil then flows back into the engine sump. This not only saves oil, but also protects engine parts from carbon deposits. In this case, oil separators can be located inside the valve covers, built into the engine, or made as a separate unit.
Principle of operation
The system works as follows. The ventilation pipe is connected to the intake manifold, where immediately after starting the engine, a vacuum is created, due to which crankcase gases are “pulled” from the pan and passing through the oil separator enter the intake, where, mixing with the incoming air, they enter the combustion chamber and burn out.
Operating principle of the crankcase ventilation system
Advantages of the ventilation system
The use of crankcase ventilation allows you to reduce the percentage of harmful emissions into the atmosphere, reduce engine oil waste, and maintain stable engine speeds when warming up, since the intake air mixes with crankcase gases and heats up, which generally has a beneficial effect on the operation of the power plant.
Flaws
Despite the presence of an oil separator, the air ducts and intake elements become dirty from the passage of crankcase gases, causing frequent failures of the devices during operation. So, on gasoline car models, the throttle valve assembly and idle speed control become coated, since they have special channels that perform an exhaust function. This can also be observed on carburetor models, for example, with a Solex carburetor equipped with a fitting for crankcase ventilation.
Carbon deposits on the throttle valve
The throttle valve assembly and gas exhaust valve on carburetors are the so-called small branch and are activated when the vacuum in the air filter is insufficient.
Symptoms of a PCV Problem
• The appearance of traces of oil in the air filter;
• Fogging of oil seals and the joint of the engine valve cover;
• Smoke from the exhaust due to oil particles and gases entering the combustion chamber;
• Traces of oil around the filler cap and on the valve covers.
Traces of oil on the filler neck and along the joint of the valve covers
In addition, these symptoms also indicate severe wear or malfunction (valve burned out, rings stuck, piston partitions burst) of the piston group and the need to check them by measuring compression.
Causes of malfunction:
• The crankcase ventilation valve is clogged or faulty;
Dirty PCV valve
• The exhaust holes in the throttle assembly or carburetor fitting are dirty;
• Severe wear of the piston group;
Functionality check
To check the operation of the ventilation system, you need to remove the cap from the filler neck with the engine running. If everything is in order, then only individual “shooting” droplets of oil may be observed, or there will be no traces of its appearance at all. Otherwise, engine oil will be thrown out of the neck.
If you cover the hole with your hand, then if the system is working properly, you should not feel any pressure on it, but when the system is under excess pressure, the gas will try to push the palm away and this force will gradually increase.
To check the serviceability of the ventilation valve, which is usually located in the intake manifold, you need to disconnect the hose from the crankcase to the valve, start the engine and close the loose fitting on the valve with your finger. If the valve is working, then the finger will feel the creation of a vacuum, and when the finger is removed from the fitting, a characteristic click will follow. Otherwise, the valve requires replacement.
Crankcase ventilation valve
Malfunction of the valve affects the composition of the fuel mixture and related problems.
In custody
If signs of crankcase ventilation malfunction are detected, it is recommended, without delaying until the next day, to begin cleaning and preventing the system in order to minimize oil waste and engine wear.
Exhaust gas recirculation valve faulty
Another possible cause of exhaust emissions from the ventilation could be a jammed EGR valve. This valve is responsible for exhaust gas recirculation, that is, for supplying part of the exhaust gases back to the engine. This is dictated only by environmental considerations and is aimed at reducing emissions of harmful substances (for example, nitrogen oxides). In severely depleted diesel vehicles, carbon deposits accumulate in the EGR valve, which over time can cause the system to seize up.
Damage to the check valve may result in the smell of exhaust gases from the air supply. Associated symptoms include decreased engine power, jerking under heavy loads, or heavy smoke from the exhaust system. To avoid defects, it is worth removing carbon deposits regularly (every 60,000 km) with a special USR cleaner. However, in some cases you will need to replace the part.
An activated Check Engine icon indicates problems with the engine system.
