Going Home in an Old Car: Should You Choose Heavy Oil (W50) or Light Oil (W40) for Safety?

The journey back home in an old car to celebrate Tet always brings a lot of emotions but also carries the worry of breakdowns on the road. For older vehicles, the challenge of continuously driving hundreds of kilometers while carrying a heavy load can be immense. One of the biggest debates before each trip is which oil to choose: W40 for lighter operation and fuel efficiency or W50 for a smoother engine that can withstand heavy loads? This article will help you analyze the condition of your machinery to make the right decision, ensuring that your trip back home in an old car is safe and smooth.

When returning home in an old car, the choice of oil depends on the wear and tear of the engine. You should choose thicker oil (W50) if the car shows signs of smoking, a loud engine, or oil consumption after previous trips; higher viscosity helps seal gaps and protects engine components under high temperatures. On the other hand, select lighter oil (W40) if your old car's engine runs smoothly, retains pressure, and you want to save fuel; however, prioritize synthetic oils to ensure heat resistance during long trips.

1. Technical challenges of the journey back home for old cars

Unlike daily commuting in the city, a journey home in an old car imposes entirely different pressures on the lubrication system.

1.1. Maximum temperature and load

When driving long distances (touring), the engine temperature will remain very high for extended periods. Coupled with carrying luggage, Tet gifts, or passengers, the engine operates at maximum capacity. With older vehicles, the cooling system often becomes less effective, causing the oil to thin out (loss of viscosity) faster than in new cars.

1.2. Technical gaps and the risk of engine seizure

An old car means wear and tear on components such as pistons, cylinders, and bearings, creating larger gaps. When the oil thins due to high temperatures on long journeys, the protective oil film can break down. This is the reason many old cars experience engine seizure while traveling home due to excessive friction.

2. When to choose W40 and when to choose W50?

For a safe journey home in an old vehicle, you need to listen to the sounds of the engine to select the appropriate viscosity.

2.1. Choose thick oil (20W-50): Cushioning for a worn-out engine

This is the safest choice for most older manual and scooter models that have been used for over 50,000 to 70,000 km without overhauling.

• Mechanism: The 50