Why Does the Radiator Leak?

[MacEzra]

Radiator leakage causes: The radiator may leak due to aging and damage. If the radiator is leaking, it is recommended to replace it with a new one promptly. It is advised not to drive when the radiator is leaking, as the lack of water or coolant will prevent the engine from cooling down, potentially leading to cylinder scuffing or bearing seizure due to excessive temperature, rendering the engine unable to start. Radiator leakage can also cause the engine to overheat due to insufficient coolant, which in turn reduces the viscosity of the engine oil, preventing the formation of an oil film between friction surfaces and increasing wear. If the radiator frequently leaks, it is recommended to have it inspected and repaired by a professional institution, and replaced if necessary.

[Gimli]

The other day, my old car had a radiator leak. When I popped the hood, I noticed bubbling and dripping at the seams. Plastic radiator tanks become brittle with age, and in winter, antifreeze freezing and expanding can easily cause cracks. Metal radiators fare even worse—a single pebble kicked up on the road can dent them and cause leaks. Then there are those rubber hoses—after five years, they’re like dried-out rubber bands, crumbling at a touch. The worst is when repair shops don’t tighten the radiator screws properly, leading to antifreeze spraying out on the highway. Now that the weather’s heating up, I recommend checking the coolant level markers monthly. If you spot any leaks, get them fixed ASAP—otherwise, engine overheating could lead to costly repairs or even total failure.

[OAthena]

My family has been in the auto parts business for over 20 years, and we've handled countless cases of radiator leaks. Generally, there are four common scenarios: the rubber seal on the plastic radiator cap deforms over time, causing hissing sounds when pressurized; the radiator itself gets corroded by coolant, developing pinholes—especially aluminum radiators which are prone to perforation; the drain valve at the bottom isn't tightened properly, leading to slow seepage; or the hose clamp wasn't secured correctly during the last repair, causing it to burst open and spray water on bumpy roads. Ignoring these minor issues can lead to overheating on the road or even engine seizure. We recommend having the mechanic inspect the radiator seams with a flashlight during every maintenance check—early detection can save you from major repairs later.

[MacMichael]

Having driven a taxi for ten years, radiator leaks are all too common. In summer, rubber hoses tend to soften and crack under scorching heat, while in winter, insufficient antifreeze concentration can cause freezing and crack the radiator. Last time, a car in our fleet had an issue with the water pump seal ring—water seeped into the bearing and fried the engine. Here’s a down-to-earth trick: when the engine is cold, place a white sheet of paper under the radiator and check the water marks the next day. If it’s leaking fast, take it to a professional shop for disassembly and inspection. Small cracks can be welded, but if it’s rusted through, just replace the radiator.