Can engine oil be used as a substitute for brake fluid?
3 Answers
No, engine oil serves as a lubricant and does not have pressure, whereas brake fluid is a pressure fluid used in hydraulic braking systems. Here is the relevant information: Brake fluid: Brake fluid, also known as brake liquid or hydraulic brake fluid, is a type of fluid made from refined diesel distillate with thickeners and antioxidants. It comes in three types: mineral oil brake fluid, alcohol-based brake fluid, and synthetic brake fluid. Hazards of substitution: If engine oil is used as a substitute for brake fluid, it will result in the inability to press the brake pedal, and the engine oil will corrode the braking system, causing damage to the vehicle's braking system and severely compromising personal safety.
I think brake fluid absolutely cannot be replaced with engine oil, as this is a major taboo. Brake fluid is specifically designed to transmit pressure and has an astonishingly high boiling point, typically exceeding 200°C, so it won't boil even when the brake discs glow red during emergency braking. Engine oil, however, is meant for lubricating the engine and has a boiling point of only around 100°C. If used in the brake system, it can easily vaporize under high temperatures, creating air bubbles that make the brake pedal feel spongy and ineffective, which could be fatal at high speeds. Additionally, brake fluid absorbs moisture to keep the system dry and prevent corrosion, while engine oil lacks this capability and instead allows moisture to accelerate aging. I've seen many cases where friends tried to save money by mixing engine oil for repairs, only to end up with brake failure, costly full system replacements, and near-accidents. Therefore, it's essential to use proper DOT-grade brake fluid and regularly inspect and replace it for peace of mind.
I've been driving for over a decade, and brake fluid and engine oil are completely different things that shouldn't be mixed up. I witnessed this firsthand when I saw a villager using regular engine oil as brake fluid on a country road. When driving downhill, the brakes felt mushy like stepping on cotton—thankfully I reacted quickly and pulled the handbrake. The reason is that engine oil is too thin and can't build proper hydraulic pressure. Plus, its strong lubricating properties can damage brake seals, leading to leaks. Effective braking relies on high boiling-point brake fluid that resists failure in emergencies. I've also noticed that in humid climates, brake fluid absorbs moisture faster, lowering its boiling point, making regular changes even more crucial. Never cut corners by substituting engine oil—it won't save you money. Instead, you'll end up spending more on repairs or even compromising safety. Always follow the manual and use dedicated fluid, changing it every 2-3 years for better performance.
