1. Excessive oil

Machine oil injection is also a standard，Not the more, the better，If the amount of oil is added too much，More resistance to the rotation of crankshafts，thus affecting power output，Increase fuel consumption。The amount of oil entering the burning room greatly increases，Increase the carbon accumulation of the burning room，Added piston motor resistance，Dreaming the engine power。At the same time, it will also cause the burning room to change the air -fuel ratio，Increases the chance of explosion，Noise will also increase with this。

2. Moderate carbon deposits

Old oil is thinner, the thinner，More and more carbon deposits。Oil is thinner and easy to chan in oil，Causes more and more carbon deposits。When replaced with new engine oil，The engine cannot adapt to the oil viscosity of the engine，May increase the speed，Then cause the engine noise。It is recommended to use high label gasoline to turn on high speed，It is best to keep it on 2500 rpm more than seabet mya box of high standard oil.，Of course, you can also prevent preventive cleaning。

3. The viscosity of the oil should be suitable

Machine oils at different levels have different characteristics，Its low temperature initiative and high temperature anti -wear、Attachment also has different performances。The viscosity and temperature of the oil are reversed，When the engine is cold，higher oil viscosity，If the oil selected is thicker，It will start motor、Battery, etc. increase additional loss。But if the oil is too thin，Under high temperature work, it is difficult to form a sufficient protective film and cause insufficient lubrication，Caused the mechanical parts to wear wear。If the vehicle manual is recommended 5W-30，and the car's noise of 5W-40 becomes larger，Then the owner needs to pay attention。It is recommended to choose motor oil.。

4. Mixing the oil

This situation is also more common，Different technical formulas used by different brands，It may produce adverse chemical reactions，Change its own characteristics，Thus cause wear to the engine，Increase noise。It is recommended that riders better not mix oil，Try to use the oil of the same brand as much as possible。If you encounter special circumstances, change different brands of oil，It is best to use the same label oil。

5. Encountered fake oil

This situation is also very possible，Because the novice driver is doing maintenance for his car，Added inferior oil。Due to the anti -wear of the "fake" engine oil、Clean、Lubrication protection and other performances are very poor，As a result, the engine pressure is too large，So wearing increased、Increase noise。As a consumer，You must know some related anti -counterfeiting knowledge，Can't just hear the way，You must know how to distinguish the authenticity of the oil。

6. The sound of cold cars is normal

Cold car status motor oil is mostly returned to the oil bottom shell，At this time, the internal device of the engine lacks lubrication，When the cold car starts, the engine temperature will become low，The lubrication performance of the oil does not meet the best state，Add the reasons for the preheating speed of the engine will cause a large noise，But the noise speed after the hot car will drop again，This is normal。If the hot car does not return to normal after the hot car，I suggest you check it out。

7. Psychological effect

This should be the majority，People have an error in different environments，The sound alone cannot determine that the sound becomes larger，It is best to measure with a decibel meter。Analysis from the technical perspective of the viscosity of the oil，5W-20、5W-30 motor oil will be slightly larger in the urban area，Normal driving at high speed，The noise will be slightly smaller。5W-40、5W-50 oil products will be less noisy during driving in the urban area，Driving at high speed，The noise will be slightly larger。

Suggestion

If you change the new motor oil，The engine sound starts to get larger，The owners don't have to worry too much，It is recommended to run in for a while before observing，If you still happen after running in for a while，It is recommended that the owner go to the repair shop to check it。Of course after replacing the new motor oil，Don't deliberately distinguish the sound of the engine，When the sound becomes lighter, this is likely to be a psychological function。

Source: car maintenance and maintenance

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