What Causes the Gurgling Water Sound When the Car Stops?

[LeElliot]

The gurgling water sound when the car stops is caused by gas in the cold exhaust pipe waiting to be re-burned. Possible reasons for sounds when the car stops include: 1. Cooling sound of the three-way catalytic converter: The normal operating temperature of the three-way catalytic converter is between 400 to 800 degrees Celsius. After turning off the engine, it gradually stops working, the temperature drops, and internal metal components expand and contract due to heat, producing abnormal noises; 2. Cooling sound of the exhaust pipe: The temperature of the exhaust pipe during cold idle is around 200 degrees Celsius, and the thermal expansion and contraction of the exhaust pipe cause abnormal noises; 3. Turbo cooling sound: The rapid rotation and friction of the turbocharger generate high temperatures. After turning off the engine, the thermal expansion and contraction become very noticeable, producing abnormal noises; 4. Abnormal noises caused by uneven cooling of the engine: The engine temperature is very high, and after turning off the engine, the temperature of various components drops at different rates, leading to gaps between internal metal parts cooling and contracting, resulting in friction and abnormal noises.

[MacCorey]

I've also experienced the gurgling water sound after parking while driving, which mainly stems from air bubbles in the cooling system. When the engine stops after running, the coolant continues to flow, and the movement of air bubbles in the pipes creates that sound. Sometimes it's caused by an imbalance in the radiator pressure. My car used to make this noise, and I worried whether the coolant was insufficient or there was a leak. After inspection, it turned out to be a poorly sealed radiator cap allowing air to enter. I suggest you check the hood temperature; if it's very hot and accompanied by high temperatures, you should immediately inspect the coolant level and expansion tank. During regular maintenance, make sure to purge air bubbles and don't let small issues escalate. Prolonged neglect could damage the water pump or thermostat. In short, this isn't a major issue but shouldn't be ignored—take it to a repair shop for a pressure test to ease your mind.

[EdenMarie]

Hearing gurgling water sounds after parking is mostly caused by air trapped in the cooling system. I remember after a long-distance drive, similar sounds came from under the car because the coolant circulation was blocked or the fluid level was too low, causing bubbles to tumble in the pipes. In such cases, don't panic. Open the hood and check the radiator water level. If it's noticeably low, top it up with coolant, but avoid adding plain water to prevent corrosion. Sometimes it's due to thermal expansion and contraction—after stopping the engine, the coolant contracts and flows back, creating noise. Regularly inspect the cooling system's seals and check for cracks in the pipes to reduce such issues. If the sound occurs frequently, visit a professional shop for air bleeding or to test the thermostat. Safety first, to avoid overheating and breaking down on the road.

[VonFelix]

The gurgling sound when the car stops is usually caused by air bubbles flowing in the coolant. It may be due to insufficient coolant or air not being completely purged from the system, causing bubbles to collide in the pipes and make noise. My previous car had the same issue, with the sound being more noticeable after cold starts. Upon inspection, it was found that the radiator cap had aged, leading to air leakage. A simple solution is to add standard coolant and perform regular maintenance to prevent this. Don't ignore it, as it increases the risk of overheating.