Where is the vent hole of the urea tank?

[VanChloe]

The vent hole is located next to the filling port on the top of the urea tank and is a vent screw. The function of the vent hole: The vent hole is mainly used to establish pressure in the urea tank. If it is accidentally blocked, the urea tank will not be able to build up normal pressure, and in severe cases, the urea tank may be sucked flat and scrapped. Since urea is prone to crystallization, it is necessary to frequently check whether the vent hole is blocked. Introduction to automotive urea: Automotive urea refers to a urea aqueous solution with a urea concentration of 32.5% and a solvent of ultrapure water. The raw materials are special urea for automotive use and ultrapure water. Its most basic function is to convert nitrogen oxides in vehicle exhaust into harmless nitrogen and water, which is energy-saving and environmentally friendly, enabling the vehicle to meet the national exhaust emission standards.

[SanMiles]

The vent hole of the urea tank is usually located at the top of the tank or on the side near the top, which you can find by opening the engine compartment. Its main function is to balance the pressure inside and outside the tank, preventing vacuum formation that could hinder urea refilling during temperature changes or when adding urea. If you ever find it difficult to fill urea or notice bubbling during refilling, chances are this small hole is clogged with debris. I've seen many owners neglect cleaning the vent hole in time, leading to fault codes in the urea system or even sensor damage. The cleaning method is actually simple: gently blow with an air gun or use a fine needle to clear it, but never use excessive force. It's recommended to check this small hole during each maintenance, especially for vehicles frequently operating on construction sites, as they are most prone to dust and mud buildup.

[DiParker]

Last time my car's urea system kept reporting faults, and after troubleshooting for a long time, it turned out to be the vent hole issue. It's usually located on top of the urea tank, and in some models, it's designed as a small protruding tube. Don't underestimate this little thing—without it, the urea tank would become a sealed container. In summer, high temperatures cause the solution to expand with no way to release pressure, and in winter, freezing can deform the tank. Once on a long trip when I was refilling urea, I noticed the fluid level wobbling but couldn't add any more. Shining my phone's flashlight revealed the vent hole was completely clogged with crystals. Now I've learned my lesson—every 5,000 kilometers, I use a cotton swab dipped in hot water to clean the hole, and basically haven't had any issues since. By the way, it's best to check it an extra time when the seasons change.

[AlexandraLee]

Locating the urea tank vent is actually quite simple: lift the hood and find the white plastic tank (usually labeled with a blue urea indicator). The small protrusion or mesh-covered hole at the very top of the tank is the vent. Crucially, it must remain above the liquid level to allow proper venting. I've seen cases where people poured cleaning agents into the vent, only to cause secondary blockages, so be cautious during cleaning: use a soft copper wire with a diameter of less than 2mm to gently clear it, or attach a soft tube to blow air through it. In the early stages of blockage, you might just notice slower refilling, but if it gets completely clogged, the urea pump can be damaged due to negative pressure, and replacing it can cost several thousand. Maintaining a vehicle requires paying attention to these small but critical components.