How to Determine a Lack of Coolant?

[FelicityAnn]

Methods to determine a lack of coolant include observing the coolant warning light on the dashboard; checking the coolant reservoir; and inspecting the water level markings on the coolant overflow tank. Observe the coolant warning light on the dashboard. If it lights up, it is likely due to a lack of coolant, though it could also be caused by excessively high engine temperatures. Check the coolant reservoir. If the fluid level is below the minimum mark (MIN), do not continue driving and promptly add coolant. Inspect the water level markings on the coolant overflow tank. The coolant level should normally be between the maximum and minimum marks. To determine if coolant is lacking, check the markings—if the coolant is below the minimum level, it indicates a shortage. Coolant replacement intervals: For vehicles that operate for extended periods, such as taxis, high-quality coolant should generally be replaced annually. For vehicles with shorter operating times, replacement can be done every two years or every 30,000 kilometers. To prevent excessive foaming, which reduces the heat exchange efficiency between the coolant and engine components, ensure the product is within its validity period when adding it. Long-life coolant can remain effective for up to three years. If suspended particles, sediment, or signs of deterioration or discoloration are observed in the coolant, replace it promptly and clean the system.

[TuckerLynn]

I always take a quick glance at that translucent plastic reservoir in the engine bay before driving, located near the radiator. There are MIN and MAX lines marked on the container, and under normal circumstances, the fluid level should be slightly above the middle. If it drops below the MIN line, it usually indicates a lack of coolant. Last week, I noticed the fluid level was almost at the bottom, and upon closer inspection, there were yellowish-white scale marks on the reservoir wall. Later, a check revealed that the hose connection had aged and was leaking. It's most accurate to check when the engine is cold in the morning, as the fluid level rises when the engine is hot, which can lead to misjudgment. If the temperature gauge suddenly spikes into the red zone during a long drive, or if a red temperature warning light appears on the dashboard, don't push it—pull over and turn off the engine immediately.

[MacAbigail]

While driving on the highway, I suddenly noticed the AC blowing hot air, and the temperature gauge was rapidly climbing—this was the real situation I encountered last year due to insufficient coolant. When I popped the hood, the upper radiator hose was scalding hot, but the lower hose was cool. After lifting the coolant reservoir cap on the passenger side (note: wait for the engine to cool down first), I found the fluid didn’t even reach the filler neck. Air in the cooling system severely impacts heat dissipation efficiency. About three minutes before the dashboard temperature warning light came on, I detected a faint sweet smell—a telltale sign of evaporating coolant from a leak.

[AutumnAnn]

After parking, crouch down and check the ground beneath the front of the car. If you spot pink, green, or orange liquid stains, it's almost certainly a coolant leak. My old car used to require monthly top-ups until I discovered the water pump seal ring was cracked. During cold starts, open the radiator cap and observe the fluid level. If you notice small bubbles rising visibly, it indicates air has entered the cooling system, often accompanied by dropping fluid levels. White crystalline deposits around rubber hose connections or rust marks along radiator seams are telltale signs of leakage.

[AlanDella]

Here's a handy daily check tip: Pinch the rubber coolant hose above the radiator when the engine is cold. Normally, it should feel firm and full of liquid. If it's easily squeezed flat, it indicates severe coolant loss in the system. Last week when helping my neighbor check his car, I found that while the auxiliary tank fluid level appeared normal, the main radiator was already half empty - this kind of false reading is particularly easy to overlook. When coolant drops 15mm below the standard line, cooling problems will occur. The most dangerous part is that the engine could overheat ("boil over") while the temperature gauge still shows normal range.