As we all know, the valve cover is usually located at the top of the engine, and the oil filler, ignition coil and other components are installed with it. With the increasing integration of the engine, the responsibilities of the valve cover are increasing.
Therefore, if the valve cover fails, it will seriously affect the running state of the engine.
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Fault case: air conditioning odor caused by aging of valve cover
A limousine entered the repair shop, and the owner complained that the air from the air conditioner smelled burnt. Maintenance personnel try air conditioning, and they can smell obvious odor during external circulation, but there is almost no odor during internal circulation. Open the engine compartment and look carefully. It is found that the oil drips on the high-temperature engine parts, releasing the burnt smell, and then being sucked into the car from the air inlet of the air conditioner.
Air conditioning outlet smells bad.
Following the trace of oil leakage, the source of oil leakage was found, which was that the valve cover was aging and cracked, resulting in oil leakage. Replace the valve cover assembly, clean up the leaked oil, and after replacing the air conditioner filter, the air conditioner odor disappears and the fault is eliminated.
Aging valve cover
The source of the above faults is the aging of valve cover and oil leakage. However, the consequence of aging of this part is not only the phenomenon of air conditioning odor.
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The valve cover is abnormal, and there are various problems.
The engine is developing in the direction of light weight and miniaturization, and many independent components in the past have begun to merge with each other and integrate into one. For this reason, in the valve cover of today’s mainstream models, seals, valves, oil mist separators, etc. are generally integrated to form an assembly.
Obviously, when the valve cover fails, its impact will be various. The following are some common phenomena:
Seal failure: Oil leaks out of the engine, resulting in oil consumption.
Increase of sludge: oil leaks into the cylinder head, camshaft and valve contact with too much oil, and sludge increases, which affects the action.
Carbon deposit in the cylinder: the oil enters the spark plug hole, which affects the spark plug flashover and forms carbon deposit in the cylinder.
Harness damage: oozing oil will flow along the harness and cause poor contact of the connector.
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Possible causes of valve cover damage
Natural aging is one of the reasons, and the failure of some other systems on the engine will also lead to the damage or performance degradation of the valve cover.
The first is the temperature. There are many engineering plastics and rubber products in the valve cover. If the engine runs at high temperature for a long time, these parts will age rapidly.
Seal on valve cover
The second is stress. If the crankcase is not well ventilated, the internal pressure of the engine will increase, which will bring additional load to the seal and make it more prone to fatigue.
In addition, human factors can not be ignored. When installing the valve cover, the bolts must be tightened in strict accordance with the order indicated by the technical data of the main engine factory, otherwise the sealing may be lax and repair may be brought.
Article source: Mahler after-sales