What Causes Brake Noise While Driving?

Do I Need to Bring Photos for Subject 4?

For the Subject 4 exam, you only need to bring your ID card; no other items are required. The Subject 4 exam consists of 50 questions, primarily presented in the form of case studies, images, and animations. The total score is 100, with a passing score of 90. Subject 4, also known as the Subject 4 theory test or driver's theory test, is part of the motor vehicle driver's license assessment. After the implementation of the Ministry of Public Security's Order No. 123, the Subject 3 exam was divided into two parts: the road test and an additional safety and civility knowledge test, commonly referred to as "Subject 4," which assesses "driving ethics." Since this test is conducted after Subject 3, it is commonly called the Subject 4 exam. Officially, however, there is no such term as Subject 4. If you fail Subject 4, you do not need to retake the previously passed exams (Subjects 1, 2, and 3). You can schedule a retake on your own, and no retake fee is required. There are no scheduling restrictions, but the validity period of the driving skills test permit is three years. If the applicant fails to complete the exams within this period, the results of the already passed subjects will become invalid.

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What Causes Insufficient Power When the Engine is Hot?

Insufficient power and sluggish performance when the engine is hot can be attributed to the following reasons: Carbon Buildup Issues: This includes carbon deposits in the cylinders, throttle body, spark plugs, and intake pipes—all critical areas affecting engine power output. Excessive carbon buildup reduces ignition energy and intake efficiency, ultimately diminishing engine power and resulting in sluggish acceleration and a muffled sound. Fuel System Problems: Using an incompatible fuel grade can reduce the vehicle's power output. Alternatively, blockages in the fuel tank vent, fuel tank switch, fuel filter, or fuel lines between the tank and carburetor may restrict fuel supply, leading to a lean air-fuel mixture and weak engine acceleration. Intake System Issues: Air is a key component of engine power. A clogged air filter due to prolonged use without cleaning restricts airflow, causing an overly rich air-fuel mixture and reduced engine performance. For turbocharged vehicles, a malfunctioning turbocharger can prevent the engine from responding effectively to throttle input, resulting in persistent sluggishness. Engine Overheating: Insufficient engine oil or coolant, or a faulty cooling system, increases engine load and impairs heat dissipation. Overheating degrades lubrication, accelerates mechanical wear, and reduces engine power, leading to poor acceleration.

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What are the differences between xenon lights, halogen lights, and LED lights?

The differences between xenon lights, halogen lights, and LED lights lie in light intensity, durability, lighting effect, and illumination width. Light intensity: Halogen lights are less noticeable in dark conditions, with a maximum output of 1200 lumens, equivalent to 1200 candles; xenon lights output 4500 lumens, equivalent to 4500 candles, which is 300% brighter than halogen lights; LED lights concentrate almost entirely in the visible spectrum, with a luminous efficiency of 80~90%, outputting 6200 lumens, equivalent to 6200 candles. Durability: The average lifespan of halogen lights is 500 hours; xenon lights can last over 30,000 hours, which is 6 times longer than typical halogen bulbs; LED lights can last up to 100,000 hours. Lighting effect: Halogen lights provide uniform illumination; xenon lights have relatively concentrated light with darker sides; LED lights have minimal light deviation and do not require filtering. Energy efficiency: Typical halogen lights consume 55W; conventional xenon lights consume 35W; LED lights consume only 1/20 of the energy of halogen lights. Illumination width: Halogen lights cover about 4.4 meters; xenon lights cover about 5.2 meters; LED lights cover about 6.1 meters.

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How to Check if a Used Car Has Been in an Accident?

Buying a used car and checking if it has been in an accident: 1. First, check the paint: Large areas of repainting will result in paint thickness outside the normal range, which can easily be detected with a paint thickness gauge. Cars that have been in accidents usually show signs on the anti-collision beams. 2. Inspect the engine compartment: If you notice screws that have been turned or unusual folds or dents, further inspection is needed. 3. Check the A, B, and C pillars: First, observe for obvious dents or bumps, then remove the door frame's rubber seal to see if the welding points are neat. Methods to determine if it's a new car are as follows: 1. Check the manufacturing date: The vehicle's manufacturing date should match the one on the certificate of conformity, which is usually hard to alter. If the manufacturing date is more than 15 days old, it's considered an old car. 2. Examine the brake discs: Most small passenger vehicles today have disc brakes (at least the front brakes). Checking the brake discs is a very reliable method. Generally, after driving more than 200 kilometers, the brake pads will leave noticeable marks on the brake discs. There is usually a 1-2 mm gap between the brake pads and the outer edge of the brake disc. After a certain distance, this will leave what is commonly referred to as a "ledge" (the "ledge" on a new car is very low).

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Can Vehicle License Plates Be Transferred When Selling a Car?

Selling vehicle license plates: They cannot be transferred. Below is a related introduction on how to identify fake license plates: 1. Observe the font of the license plate: Since the font of motor vehicle license plates follows a unified national standard, but they are not produced uniformly nationwide, the size and structure of the fonts may vary. However, each province has its own characteristics in motor vehicle license plate production. With careful observation, it is not difficult to distinguish. Genuine plates, i.e., standard license plates, feature uniquely designed fonts with intellectual property rights, offering a good visual experience. Counterfeit plates often have a background color that is too blue or yellow, with fonts that are either too thin or too thick, or abnormalities at the bends of the characters. 2. Observe the coloring of the license plate: Due to differences in the quality and composition of the paint used for the base plate of vehicle license plates, genuine and fake plates will differ. Genuine plates are colored on the front with imported paint through a roller, resulting in even coloring that only covers the raised parts. Fake plates are usually painted with a brush or pen, appearing uneven with visible brush strokes. Additionally, some recessed areas may also be colored, giving an overall impression of rough craftsmanship. 3. Observe the reflectivity of the license plate: Genuine plates do not reflect sunlight but reflect under direct light. Fake plates may appear shiny from certain angles under sunlight but remain dull under direct light, without any reflection.

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Should the Roewe RX5 Plus use 92 or 95 octane gasoline?

According to the official vehicle manual recommendation, the Roewe RX5 Plus should use 92 octane gasoline. In addition to checking the appropriate gasoline grade in the vehicle manual, the Roewe RX5 Plus can also find this information on the fuel tank cap, which will be clearly marked. Typically, the gasoline grade can also be determined based on the engine's compression ratio. Vehicles with an engine compression ratio between 8.6-9.9 should use 92 octane gasoline, those between 10.0-11.5 should use 95 octane gasoline, and if the compression ratio is higher, 98 octane gasoline should be selected. However, with the application of some new technologies nowadays, the gasoline grade cannot be solely determined by the compression ratio. High compression ratio engines can also be tuned to use lower octane gasoline. This is because, apart from the compression ratio, other factors such as ignition timing, turbocharging technology, and Atkinson cycle technology also play a role. Generally speaking, the higher the gasoline grade, the higher the octane number and the better the anti-knock performance. 92 octane gasoline contains 92% isooctane and 8% n-heptane, while 95 octane gasoline contains 95% isooctane and 5% n-heptane. If the Roewe RX5 Plus occasionally uses the wrong gasoline grade, simply switch back to the correct grade after the current tank is used up. However, long-term use of the wrong gasoline grade can have the following effects: For vehicles recommended to use lower octane gasoline, using higher octane gasoline will not cause damage, but the increase in octane number will change the fuel's ignition point, leading to delayed combustion in the engine. This means both the engine's power output and thermal efficiency will decrease, resulting in poorer performance as experienced by the driver. For vehicles recommended to use higher octane gasoline, using lower octane gasoline can cause engine knocking. This is because the significantly lower octane number reduces the fuel's ignition point, causing it to ignite prematurely during the compression stroke. If the fuel ignites before the spark plug fires during the compression stroke, resistance will occur during the upward stroke. This resistance makes the engine run very unstably. If the knocking is imperceptible, it only increases noise without obvious damage to the engine. However, noticeable knocking indicates severe engine conditions, where the vibrations not only affect driving stability but also cause abnormal wear on the pistons and cylinders, potentially leading to cylinder scoring in severe cases.

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What Causes Brake Noise While Driving?

Do I Need to Bring Photos for Subject 4?

What Causes Insufficient Power When the Engine is Hot?

What are the differences between xenon lights, halogen lights, and LED lights?

How to Check if a Used Car Has Been in an Accident?

Can Vehicle License Plates Be Transferred When Selling a Car?

Should the Roewe RX5 Plus use 92 or 95 octane gasoline?

Does replacing only one tire have any impact?

Does the RAV4 have a heated rearview mirror function?

What vehicles can be driven with an A1 vocational qualification certificate?

What Does the Wrench Symbol Mean on a Car?