No, 5W40 motor oil is actually slightly thicker than 5W30 motor oil. The numbers in the oil's viscosity rating represent its flow characteristics at different temperatures. The "5W" part of the rating indicates the oil's flow characteristics in cold temperatures, with lower numbers indicating better flow. The "40" or "30" part of the rating indicates the oil's flow characteristics at high temperatures, with higher numbers indicating thicker oil. Therefore, 5W40 motor oil is slightly thicker than 5W30 motor oil at high temperatures. **

The difference between 5W40 and 5W50 is in their viscosity at different temperatures. The numbers before the 'W' indicate the oil's viscosity in cold temperatures, with lower numbers indicating better flow in cold conditions. The numbers after the 'W' indicate the oil's viscosity at operating temperatures, with higher numbers indicating better viscosity at high temperatures. Therefore, 5W40 has better cold flow and slightly lower viscosity at operating temperatures compared to 5W50. **

5w40 motor oil is a popular choice for many engines because it offers a good balance between protection and performance. It has a viscosity rating of 5 in cold temperatures, which means it flows well at startup, and a viscosity rating of 40 at high temperatures, which means it provides good protection under heat and stress. However, whether 5w40 motor oil is better for your engine depends on the specific requirements and recommendations of your vehicle's manufacturer. It's important to consult your owner's manual or a professional mechanic to determine the best motor oil for your engine. **

Yes, a 5W40 motor oil is slightly thicker than a 5W30 motor oil. The numbers in the oil's viscosity rating indicate its flow characteristics at different temperatures. The first number (5W) represents the oil's viscosity in cold temperatures, while the second number (40 or 30) represents its viscosity at operating temperatures. Therefore, a 5W40 oil will be thicker at high temperatures compared to a 5W30 oil. **

Yes, you can mix motor oil of the 10W40 and 5W40 varieties. Both oils are designed for similar applications and have similar viscosity characteristics. Mixing them will not cause any harm to your engine. However, it is always best to use the same type and viscosity of oil recommended by your vehicle manufacturer for optimal performance. **

The numbers in the oil designation, such as 5W40, refer to the oil's viscosity at different temperatures. The first number (5W) indicates the oil's viscosity in cold temperatures, with lower numbers indicating better flow in cold weather. The second number (40) indicates the oil's viscosity at operating temperature, with higher numbers indicating thicker oil. Therefore, 5W40 oil is thinner at cold temperatures and thicker at operating temperatures compared to, for example, 10W30 oil. Different vehicles and engines may require different oil viscosities based on their operating conditions and manufacturer recommendations. **

For an old four-cylinder BMW, it is generally recommended to use a 10W40 oil. This viscosity is suitable for older engines and provides better protection at higher temperatures. However, it's important to consult the owner's manual or a professional mechanic to ensure the best oil choice for your specific vehicle and its condition. **

In Germany, a 5W40 oil would be more suitable than a 10W40 oil. The "W" in the oil viscosity rating stands for winter, and the lower the number before the "W," the better the oil will perform in cold temperatures. Since Germany experiences cold winters, a 5W40 oil would provide better cold-start protection and flow compared to a 10W40 oil. Therefore, it is recommended to use a 5W40 oil for better performance in the German climate. **