Valve cover: leakage and its elimination

2024 Author: Erin Ralphs | [email protected]. Last modified: 2024-02-19 11:41

During the operation of the car, the motorist has to face various problems that arise with his car. One of these is a valve cover leak. We will talk about why it occurs and how to eliminate it in this article.

Valve cover and seal

Any driver who has seen what is under the hood of his car knows the location of the valve cover. It protects the mechanism, closing it from outside influences. In addition, protection against oil leakage is provided. The element is attached to the cylinder head with bolts and a special gasket cut to fit the shape of the head and cover.

Sufficient tightness depends on it. An oil leak indicates the poor condition of the gasket. And in this case, it will need to be replaced.

However, before proceeding with the repair, you need to understand the reasons that led to the depressurization of the part, because otherwise the seal will have to be changed again and again.

Valve cover oil

The cause of any lubricating fluid leak, no matter howit did not occur at the junctions of the engine elements, mainly due to poor crankcase ventilation. It can be not only a valve cover, but also a gasoline pump, and a distributor, and more.

During operation, part of the exhaust gases escapes from any piston, through its seal they seep into the crankcase. If the power unit is new, then the amount of leaking gases will be minimal. But with a good run of exhaust gases, a lot is gained in the crankcase, and in the end, excess pressure forms and the valve cover flows. To reduce it, new cars have an additional ventilation system designed specifically for the crankcase.

Crankcase ventilation

Gasoline power units are equipped with two types of ventilation: for idling and for high speed operation. Both systems consist of rubber tubes, due to which gases are sucked out into the intake manifold. Such a valve closes the system at idle. If it does not function, then this will cause the formation of a very lean mixture in the intake manifold. As a result, the engine will begin to shake or, even worse, stall.

In order to prevent crankcase gases from escaping with oil dust, an oil separator is installed in the valve cover. It can get clogged with soot and not work. Then the oil will penetrate into the intake manifold through the filter, which, of course, will cause the engine to smoke.

An injection engine has one exhaust pipe, butcloser to the throttle valve, the channel is divided into two. The one that has a larger diameter enters the collector up to the damper, and the smaller one, which is usually clogged with slag, after it. Through this channel of smaller diameter, ventilation is realized at idle, and through the second - when the damper is open. If the channels become dirty and ventilation is not carried out, then the exhausts form such a strong overpressure in the motor that neither the gaskets nor the stuffing box can withstand. That's why crankcase gases begin to flow out.

If it is found that the valve cover is leaking, before repairing the breakdown, it is necessary to restore the operation of the ventilation system so that even with a thousand revolutions the cardboard on the valve cover can be tightly pressed against it. Indeed, with a worn mechanism, this cannot be obtained even at two thousand revolutions, because the exhaust will break through into the crankcase, and the oil will continue to flow again and again.

Rinse the lid

When it is found that the valve cover is sweating, it is removed and washed, and the seal is changed. You may be surprised by the result. The main thing is not to forget about lubricating the washer and bolts with which the valve cover is fixed. When washing, you should try to completely wash the oil separator so that the mesh in it is at least slightly cleaned. When reinstalling the cover and tightening the nuts, be careful not to strip the threads or crush the part.

16V

On the other hand, if you constantly maintain the oil level, regularlyadding it, then there is nothing wrong with oil leaks from under the valve cover. But with a 16V motor installed, for example, on the Lacetti, in which the candles are in the recesses, this malfunction can result in a failure of the ignition system. Therefore, the Lacetti valve cover in this case must be removed, and the leak must be eliminated.

Replacing gasket

To replace the gasket, you need to take care in advance of the availability of all components, that is, a new gasket, sealant and degreaser.

Replacement is done on a cold engine to avoid burns and injury due to hot parts.

The procedure is as follows:

1. The car is driven into a garage or onto a regular flat area, the hood is opened.
2. Remove the filter cover and unscrew the bolts.
3. Remove the remaining fasteners and the cover itself from the cylinder head.
4. The connections of the elements are cleaned of the existing sealant and degreased.
5. Process a new part with a sealant and assemble in reverse order.

After the replacement is made, the head must be wiped and the engine started. If a leak is detected again immediately, most likely, the gasket or sealant was of poor quality or the installation was carried out in the wrong sequence.

To avoid negative consequences, all parts, including the Opel Astra G valve cover, on which the mentioned 16V engine is installed, gaskets, sealants and everythingthe rest should be purchased from trusted auto parts stores.