What kind of oil should be added to the oil-water separator?
2 Answers
Lubricating oil is added inside the oil-water separator. No oil addition: In fact, the oil mist lubricator adds oil not only to the mechanical valve but also to the rear cylinder. The one on the left is the oil-water separator + pressure regulating valve, which does not require oil addition. Oil addition: The one on the right is the oil mist lubricator, which requires oil addition. The oil quantity is marked on the cup, and the adjusting valve above is used to regulate the oil addition amount. Its main function is to lubricate the moving parts in the pneumatic control system. For lubricating oil, you can refer to SMC requirements: Turbine Oil No.1. Oil-water separator: It is generally used in diesel vehicles, installed near the fuel tank to separate water from diesel fuel. Diesel flows from the fuel tank through the oil-water separator, then to the diesel filter, before entering the diesel pump and high-pressure oil pump.
As a newbie who just got a diesel SUV, I was initially confused about whether the fuel-water separator needed oil. After consulting a mechanic, I learned that you absolutely must not add oil to it; it's a device specifically designed to separate water from the fuel, aiming to prevent water from entering the engine and causing corrosion. Every time after driving, I check the small valve under the separator, unscrew it to let the water drain into a container—remember to do this while the engine is running, about every 5,000 kilometers. If there's too much accumulated water, the filter element might need replacement. When adding anything, it's diesel that goes into the main fuel tank, not the separator itself. At first, I mistakenly thought it required adding engine oil, which clogged the pipes and cost me 200 bucks to clean and fix. Now, I've made it a habit to regularly drain the water to keep it clean, protecting the engine and saving money, making driving much smoother.