To protect the timing belt from dirt, foreign objects and water, a special cover is installed on the valve of the car engine. It serves as a fuse against external factors and protects the engine from the inside from oil loss. The part is attached to the cylinder block with bolts; a special gasket of the same size is used under it. Having identified oil leakage, you should find out the causes of the problem.
Obvious engine oil leaks
- Chipping, a crack directly on the neck of the cylinder block - in the area where the head is connected to the rest of the cylinder.
- Leak through bolt holes.
- Leaks also occur on the lid itself, in cases where the object itself has undergone deformation or inadvertently damaged by something, as well as due to defects in production.
What is the reason for the leakage of the oil liquid
1. The most common and easily treatable cause of leakage at the bolt site or under the cover is a pressure surge in the internal system.
When oily fluid oozes out of the gap (under the cover), this most likely indicates increased pressure or a leaky rubber gasket installed under the cover on the cylinder head. The gasket, as a high-wearing consumable, is constantly subject to temperature changes, expansion and contraction. During operation, its elasticity changes, cracks appear, it can simply crumble and stop creating a vacuum for engine parts. To stop the oil leak, you should restore the tightness of the cover, just replacing its obsolete rubber part with a new one.
2. Another cause of the leak is more serious. It is necessary to find out what triggered the pressure surge inside the engine. But before that, you need to change the pressure level.
How to measure blood pressure
The pressure is generated by a special pump. This is necessary so that the lubricant in the gas distribution mechanism circulates better through the channels in the engine itself. Each engine can have its own oil pressure indicator. This information is clearly indicated in the documentation accompanying the machine's manual.
The corresponding sensor on the instrument panel will light up when the oil pressure drops. However, with increased pressure, it will not give any signals. And the level can be determined only with the help of third-party devices. To do this, a measuring liquid pressure gauge must be connected to the motor. The readings will allow you to determine what exactly triggered the oil leak: a gasket requiring replacement or a pressure surge.
So, if high pressure arose due to a malfunction of the lubrication system, the next step is to assess by eliminating violations in the following order:
There is no ventilation inside the crankcase
This is the most common breakdown on AvtoVAZ vehicles. It occurs when free gas exchange becomes impossible in the engine, gases concentrate inside the engine and provoke high pressure on the cover. So the oil does not find a cavity in the closed space and seeps out from under the valve cover. This can also cause oil to flow directly into the air filter.
What prevents the accumulated gases from escaping to the outside? Causes:
- clogged oil separator mesh inside the crankcase;
- the ventilation system hoses are attached to the fittings, and dirt has accumulated inside them.
How to fix the situation? Wash the mesh and fittings from carbon deposits and build-ups.
The oil filter itself is clogged with soot and dust
The oil in the cylinder head moves through narrow channels. In the case of low-quality oil or its fake, the motor is subject to constant overheating, soot and dirt can accumulate inside, the channels become narrower, because everything that is superfluous settles on their walls and on the oil filter. This provokes an increase in pressure on the walls of the channels, and from here a leak forms from under the cover.
The same happens if you do not replace the oil filter for a long time. It just ceases to let the engine oil pass through, and the pressure pushes it out.
How to solve a problem? Flush the lubrication system with an appropriate flushing agent and then install a new oil filter.
The valve has broken
A pressure reducing valve is located in the oil pump. If it is closed and jammed, then this definitely provokes an increase in oil pressure. A similar thing happens (rarely) if foreign bodies are clogged inside the pump or soot and dirt get into.
How to solve a problem? The oil pump is removed, the valve is carefully disassembled and cleaned from the inside.
How to choose the right valve cover gasket
It should only be an original spare part. Compare it with the serial number from the catalog. As a rule, high-quality consumables for this purpose are made from good elastic rubber, without smudges, sagging and variations in thickness in one product. All these little things will keep the engine tight for longer.
Use sealant when installing the gasket or not? There are several opinions. Someone gives arguments against this method of sealing, and a number of craftsmen complete engine repairs in this way in the event of an oil leak.
If the valve cover has already changed, has a slightly uneven surface, then for greater adhesion to the cylinder head, it is allowed to apply sealant. But this should be done in a thin layer. If the mating surfaces are perfectly flat and do not bother you, then you can do without a sealant.
There are cars, the design of which is not provided for the installation of a gasket. In this case, the use of a sealant must be performed without fail.
How to prevent oil from leaking next time
- In order to avoid situations with engine oil leakage in the future, simple rules should be followed:
- In time for specialists to change the oil in the engine. The same applies to compliance with the timing of replacement parts - gaskets, as well as the oil filter.
- Purchase an oil that is suitable for your engine type, high-quality, licensed, from trusted sellers and suppliers.
- Prevent dirt, foreign liquids, objects, foreign chemicals from entering the lubrication system.
- When replacing the gasket and oil filter, do not spare money to purchase original parts.
- In the case of using a sealant, it should be lubricated with a very thin layer. It is important to ensure that the sealant does not smear the elements of the timing itself.
- For any technical inspection, insist on measuring the oil pressure inside the lubrication system. In case of signs of increased pressure, you should immediately contact a repair shop to eliminate possible problems.
- Prevent situations where the engine overheats.
- Monitor the serviceability of the crankcase ventilation mechanisms.
- The bolts to the valve cover should be screwed in until they stop, but they should not be overtightened so as not to provoke a crack.
How to change the valve gasket
As described, the most common cause of oil leakage is a leaky gasket.
The procedure is performed on a cold engine. It is replaced in the following sequence:
- Place the car on a flat surface, open the bonnet.
- After removing the filter cover, unscrew all bolts. The cover is removed from the cylinder head.
- Remove worn gasket. All connections of the elements must be cleaned from the previously applied sealant. Degrease the parts.
- Treat the new part with a layer of sealant.
- Collect everything in reverse order.
- It remains to wipe the head and turn on the motor.
If the leak is re-identified, the selected gasket and / or sealant is obviously of poor quality. Or the parts were re-assembled in the wrong order.
