Why Does the Radiator Burst?

[LaLayla]

The radiator may burst when overfilled with water, as summer heat causes expansion and excessive pressure. Below are relevant details: 1. Concept: An automobile radiator, also called a heat exchanger, is a key component in the vehicle's cooling system. Its function is to dissipate heat - coolant absorbs heat in the water jacket, releases it when flowing through the radiator, then recirculates to regulate temperature. It forms part of the engine assembly. 2. Working Principle: As a crucial element in water-cooled engines, the radiator serves as a vital component in the heat dissipation circuit. It absorbs cylinder block heat to prevent engine overheating. Given water's high specific heat capacity, the temperature rise after absorbing cylinder heat remains moderate, allowing heat transfer via the liquid coolant circuit.

[VanMelanie]

The other day at the repair shop, I saw a car with a burst radiator, and the owner looked really frustrated. The most common reason for a radiator bursting is excessive internal pressure that it can't handle, like when the pressure relief valve in the radiator cap fails, and the cooling system can't vent trapped air—just like blowing up a balloon until it pops. Another reason is when the antifreeze is too dirty or old, corroding the radiator until it becomes as brittle as paper, making it prone to cracks after driving on bumpy roads for too long. Extreme weather can also be a culprit—using tap water as coolant in winter can cause it to freeze and expand, bursting the radiator, while summer heat and traffic jams can lead to boiling and pipe bursts. I saw two cases like that during last year's hottest days. Additionally, vehicle collisions or a broken fan causing overheating can also ruin the radiator. It's important to get into the habit of checking the temperature gauge regularly.

[OAshlyn]

Radiator bursts can be attributed to internal and external factors. The primary internal culprit is pressure loss of control—when the pressure relief valve in the radiator cap gets rusted shut, steam can't escape once the boiling point exceeds 130°C, causing the tank to rupture. Additionally, if the engine head gasket fails, high-pressure gas from the cylinders can invade the cooling system, exerting several times the normal pressure and instantly bursting the radiator. External causes mainly involve physical damage, like road debris hitting the radiator fins or substandard coolant corroding the tank over time, leading to leaks. The most bizarre case I've seen was a DIYer adding radiator sealant that solidified into chunks and cracked the welds. Regular coolant replacement and radiator grille cleaning are crucial.

[WilliamMarie]

Radiator bursts are often caused by multiple factors leading to pressure imbalance. The cooling system is originally designed to withstand about 1.1 bar of pressure, but when the thermostat sticks or the radiator fan fails, the coolant can exceed its boiling point and boil violently. If the radiator cap's pressure relief valve also fails at this time, the pressure will exceed the plastic tank's tolerance limit. Another scenario is long-term vehicle inactivity causing coolant sedimentation and rust, thinning the radiator's inner walls until they crack under thermal expansion and contraction. Extra caution is needed in northern winters - coolants with excessive water content can freeze into icicles that pierce radiator pipes like knives. I recommend performing a cooling system pressure test annually before winter.

[JudahDella]

Simply put, the radiator couldn't withstand the pressure and burst. There are three common causes: First, excessive pressure in the cooling system, possibly due to a faulty radiator cap or a blocked water pump causing backpressure. Second, the radiator itself has aged, and the plastic components have become brittle from repeated thermal cycling. Third, external damage, such as freezing cracks in winter or collision damage in an accident. Special attention should be paid to the failure of antifreeze. This fluid not only prevents corrosion but also lowers the freezing point. If it expires, it becomes like ordinary water and is prone to freezing and expansion. I once saw a cross-section of a radiator in a repair shop, and the cracks all started from the most severely corroded areas, so regularly replacing antifreeze is truly crucial.