What is the reason why the car oil extraction hose cannot be inserted?

[DiJoshua]

There is a ping-pong ball with a diameter of about 2CM in the oil pipe, so the pipe cannot be directly inserted. You can use a slightly rigid hose with a diameter of 4-6 mm, rotate it while inserting and pulling, squeeze it in from the side of the ping-pong ball, and then you can directly insert the pipe. Fuel tank structure: Because the fuel delivery pipe of many cars is connected to the side of the fuel tank, if the oil extraction pipe is too hard, even if it is inserted into the fuel tank with great difficulty, the pipe will be parallel to the gasoline liquid level and cannot reach the fuel tank liquid level, so oil extraction is still impossible. Fuel tank anti-overflow check valve: To prevent gasoline from leaking from the fuel filler port when the vehicle rolls over or tilts, a check valve is designed at the connection between the fuel delivery pipe and the fuel tank. Its function is to ensure that gasoline can enter the fuel tank from the fuel delivery pipe, but the gasoline in the fuel tank cannot flow back to the fuel delivery pipe. This check valve is actually very simple, and most check valve structures will not cause too much interference to the pipe insertion for oil extraction.

[DelJulian]

Once I encountered this issue and found that the oil extraction hose couldn't fit into the fuel filler neck mainly because the hose diameter was too large, possibly exceeding the inlet size of the fuel pipe. Modern vehicles are designed with anti-siphon valves or curved pipes to prevent accidental fueling with low-quality fuel or fuel theft, making it impossible to insert an overly thick hose. Additionally, if the fuel filler neck is clogged with dirt or blocked by foreign objects, it can also hinder the hose. I've tried using a thinner hose or slightly lubricating the tip, which allowed it to slide in easily. However, forcing it in may damage internal components, leading to bigger problems. Therefore, it's advisable to first measure whether the hose size matches, clean the fuel filler neck, and if it still doesn't work, take it to a professional repair shop for inspection. Safety first—don't rush to try again, as it could cause a fire or fuel leakage.

[Imogen]

I love doing my own car maintenance, but when it came to oil extraction, the hose just wouldn't fit into the filler neck. The main reasons are either the hose was too large or the angle was wrong, forcing it would easily get stuck. Some cars have anti-theft rings in the filler neck, and if the hose is too stiff or thick, it simply can't push through. I later solved it by switching to a smaller diameter hose, or you can try a more flexible plastic hose. Another common issue is carbon buildup or debris clogging the entrance, which can be cleared with a fine brush. Need some lubrication? Use silicone oil, not flammable stuff, and don't rush or force it to avoid damaging the hose and causing bigger problems. Actually, regular cleaning of the filler neck during maintenance can prevent this issue, saving both money and hassle. DIY is fun, but don't fall into the pitfalls.

[LeJosephine]

After working in the repair industry for a long time, I've seen many car owners complain about the oil extraction hose not fitting in. It usually comes down to size mismatch or fuel tank design issues—either the hose is too large or the fuel filler neck has anti-theft structures blocking it. Sometimes, aging or deformed fuel lines can also jam the hose. The solution is simple: don't force it. Measure the hose diameter for a proper match and gently insert it. If that doesn't work, switch to a thinner hose or clear the obstruction. Forcing it can damage valves, cause leaks, and lead to hazards. Timely maintenance can prevent major issues. Even small safety-related matters shouldn't be overlooked when it comes to safe driving.