How to check the valve cover, the most important accessory that affects the oil burning of French cars?
Let’s take the Peugeot Citroen 1.6T engine, which has the largest inventory at present, as an example. The valve cover is damaged from 70,000 km to 100,000 km, which is not a common problem of Peugeot Citroen. BMW, Buick, Chevrolet, Ford and other models are also prone to oil leakage when driving for 100,000 kilometers, or the negative pressure is wrong, and the air intake fault is reported, or there is a fire, or the oil consumption is obviously abnormal.
Distinguishing between true and false valve cover
First, the original valve cover must be used. Replacing the original valve cover will solve the problem. The original Peugeot Citroen valve chamber is produced by Meijia, and there are many parallel imports in the market, and 95% of the quality is very poor. If there is no reliable channel to purchase, the probability of buying parallel valve chamber covers is as high as 95%. Once the valve cover of parallel imports is used, it is highly probable that it will not work well, and there are still many potential safety hazards, such as the engine idling for one hour, the engine climbing up a steep slope and stepping on the accelerator, and when the negative pressure inside is high, the engine oil will leak from the valve cover pad. In severe cases, there is too much engine oil in the engine room, which flows to the exhaust manifold below. Under the high temperature of the exhaust manifold above 400 degrees, it is easy to cause the engine to catch fire, and the potential safety hazard is great.
Someone replaced the aluminum alloy cover. The aluminum alloy cover is not the original one, which is not easy to use, because when the valve cover is installed, the plastic one has tension, and the aluminum alloy has no tension at all, which will lead to oil leakage after a period of use. Of course, if the original factory is aluminum alloy, we must change the original aluminum alloy cover, and if the original factory is plastic, we must change the original plastic cover.
Second, how to identify the original valve cover. It is very difficult to tell the difference just by looking at the valve cover. Look at the picture below: The red spots in the aging and damaged valve cover have been damaged and fallen off, resulting in serious engine oil burning.
How can two new valve covers distinguish between good and bad? The simplest way is to compare the gluing at the seams. Figure 1 shows the gluing seams of brand parts, and Figure 2 shows the seams of the original Meijia. The glue in the joint position in Figure 1 is rough, which can be seen by naked eyes. The glue in the original factory of Figure 2 is uniform and tidy.
The glue applied to the seal under the oil cover, Figure 3 shows the glue of brand parts, and Figure 4 shows the glue of the original valve cover, which is also very different. So if you want to change it, just change the original parts.
Third, matters needing attention in replacing the 1.6T valve cover. Many riders have encountered the problem of oil leakage from the valve cover or oil burning due to the aging of the one-way valve in the valve cover, and the problem has not been solved after replacement. In fact, there are three reasons. Remember the following three points, and it is not a detour to replace the valve cover.
Fourth, the negative pressure value that everyone pays the most attention to. Many people are unfamiliar with the negative pressure of the 1.6T engine. Today, we will provide this value for you to facilitate the inspection of engine oil in the future.
First of all, there must be a tool to test the negative pressure value. After the hot car is started, the negative pressure value is detected. One end of the hose is inserted into the filler of the oil dipstick, and the other end is set to mbar, so that the test can be started. The normal value of 1.6T has a slight change around 35. If it is lower than 25, it will obviously start to consume oil. At this time, it is impossible to observe it by using the traditional method to open the oil cover and pull out the oil dipstick, which can almost approach the oil consumption of 3000-4000 kilometers per liter. If it is lower than 12, there will be obvious abnormal consumption of engine oil, and it is common to consume one liter of engine oil for hundreds of kilometers or one thousand kilometers. Especially in the early aging of the valve cover, the oil consumption of low-speed driving in the city is not obvious, and the oil consumption of high-speed driving will be significantly higher.
Precautions for valve cover replacement
First, the original valve cover, which is an essential element;
Second, after disassembling the valve cover, the cooling time should be sufficient;
Third, install the screws in sequence according to the standard torque.
As long as we pay attention to the above three points, we can solve the problem well, and the valve cover problem is not a design defect.
summary
With regard to the problem of burning engine oil caused by the valve cover of French vehicles, we should pay attention to two points: first, replace the original valve cover; Second, find professional checkpoints, such as legal system specialization and sunshine craftsman shop. The burning oil caused by the valve cover can be 4000 liters or 600 liters, which is possible. In the initial stage, it is not serious to consume one liter of engine oil for 4000 kilometers, and it will consume one liter of engine oil for 1000 kilometers or hundreds of kilometers in the later stage. To prevent the engine from burning engine oil prematurely, we can regularly use the cleaner with general PNF technology to keep the oil circuit clean and clean the ternary system at the same time, so as to reduce carbon deposition, thus delaying the occurrence of engine oil burning.