What are the reasons for a sudden decrease in coolant?
2 Answers
The main reason for a sudden decrease in car coolant is a coolant leak. The causes of coolant leaks include radiator damage, poor sealing of the upper and lower water chambers; loose connections and poor sealing at the overflow tank, water pump interface, and cooling system pipelines; damaged cylinder gasket; warping at the joint between the cylinder head and the engine block or loose cylinder head bolts. Solutions for car coolant leaks: Replace the radiator; tighten the screws at the overflow tank, water pump interface, and cooling system pipelines; replace the cylinder gasket; tighten the cylinder head bolts. Method for replacing coolant: Before completely replacing the coolant, conduct a thorough inspection to check for any signs of leaks or cracks in the pipelines, with a focus on the five-way hose. The five-way hose gets its name from having five connection interfaces for different parts. The coolant flows through the five-way hose and is distributed to various parts of the car to function. If there is a coolant leak in this part, the hose should be replaced or the interface re-secured as needed. Drain the old coolant, then flush the liquid channels with clean water. Add clean water to the coolant reservoir, then continuously inject water into the reservoir to allow it to flow through the engine cooling system. Start the engine and let it idle for 3 to 5 minutes to circulate the water. The water initially flowing out of the reservoir will be slightly pinkish. Continue adding clean water until the water coming out is clear. Remember to remove the heater hose and drain the water from the heater core. After draining for about an hour, add the new coolant through the radiator hose, which allows the coolant to flow into the radiator quickly. Then add another bottle of coolant to the reservoir until it is nearly full. Start the engine and let it run for about 10 minutes. At this point, the coolant level will drop slightly as air is expelled from the cooling system. Add more coolant until it reaches the "MAXT" mark on the reservoir.
Discovering a sudden drop in coolant levels is something I've experienced several times, usually due to a leak in the cooling system. The most common causes are aging hoses or cracks in the radiator, especially after high-temperature driving or frequent acceleration, as rubber hoses are prone to drying out and leaking. The inspection method is simple: after parking, check under the car for green or pink stains—those are signs of coolant. Additionally, a damaged water pump seal can lead to slow seepage, though it may not be immediately noticeable. Don’t rush to top it off; first, locate the source of the leak before refilling, otherwise, you’ll waste money without solving the root issue. During daily driving, pay attention to rough road conditions, as bumps and vibrations can worsen existing problems. Remember to have a technician thoroughly inspect the entire cooling system during each maintenance service—early leak detection can prevent major repairs. In short, unexplained coolant loss is often due to a leak, so don’t delay addressing it to avoid engine damage.
