Radiator Leak: Signs, Causes, and What to Do Next
When your car’s radiator, a key part of your engine’s cooling system that circulates coolant to prevent overheating. Also known as a cooling radiator, it’s one of the most critical components keeping your engine from turning into scrap metal. starts leaking, you’re not just dealing with a puddle under your car—you’re racing against time. A small drip today can mean a seized engine by tomorrow. Most people ignore it until the temperature gauge spikes, but by then, it’s often too late. Radiator leaks don’t fix themselves. They get worse. And they don’t just cost money—they cost you time, safety, and sometimes your whole car.
The coolant, the fluid that flows through the radiator and engine to absorb and transfer heat. Also known as antifreeze, it’s the lifeblood of your cooling system. isn’t just water—it’s a mix designed to handle extreme heat and cold. When the radiator develops a leak, that coolant escapes. You might see green, orange, or pink fluid on your driveway. Or you might just notice your car running hotter than usual. Some leaks are obvious. Others? They hide inside the engine bay, leaking slowly into the exhaust or onto hot parts where it evaporates before you even see it. A bad radiator cap, the seal that maintains pressure in the cooling system to raise coolant’s boiling point. Also known as cooling system pressure cap, it’s often the hidden culprit. can cause pressure loss, making coolant boil off even if the radiator itself is fine. And if your radiator’s old, rusted, or clogged, it’s just waiting to crack under stress.
Engine overheating, when the engine temperature rises beyond safe limits, often due to cooling system failure. Also known as thermal runaway, it’s the direct result of a failing radiator. doesn’t just make your car shut down—it can warp the cylinder head, blow the head gasket, or melt internal parts. That’s not a repair. That’s a total loss. The good news? Most radiator leaks start small. If you catch them early, you can fix them for under £200. If you don’t, you’re looking at £1,500 or more. Check your coolant level weekly. Look under the hood after parking. Smell for sweet, syrupy fumes. Listen for hissing when the engine’s hot. These aren’t just tips—they’re survival steps.
Below, you’ll find real-world guides from drivers who’ve been there. Learn how to spot a radiator leak before it kills your engine. See what causes the most common failures. Find out if you can patch it yourself—or if you need to walk away. We’ve pulled together the most useful posts on radiator lifespan, coolant system problems, and how overheating affects other parts of your car. No fluff. No theory. Just what you need to know to keep your car running and avoid a roadside disaster.
