Here's a breakdown:
* Pros: 10W-40 offers a good balance of low-temperature fluidity (the "10W" part) and high-temperature protection (the "40" part). Many older engines, particularly those found in high-mileage vehicles, were designed to work well with this viscosity. It can provide decent protection against wear and tear.
* Cons: High-mileage engines often have more wear and tear, leading to increased oil consumption and potential leaks. A thicker oil might be better at sealing these leaks, but a 10W-40 might not be thick enough in some cases. Additionally, modern engines, even older ones, may benefit from thinner, higher-quality oils designed to meet specific standards (like those indicating improved fuel economy or better high-temperature protection).
The best approach is to check your owner's manual. It will specify the recommended oil viscosity and other specifications (like API certifications) for your vehicle. This is the most important factor to consider.
If your owner's manual doesn't specify 10W-40, or recommends a different viscosity (e.g., 5W-30 or 5W-40), it's best to follow the manufacturer's recommendation. Using the wrong oil can lead to engine damage.
In short: 10W-40 *might* be okay for your high-mileage vehicle, but it's crucial to consult your owner's manual first. If you're unsure, consult a qualified mechanic. They can assess your engine's condition and recommend the most appropriate oil for its needs.
