Coolant Leaks: Signs, Causes, and What to Do Before It Costs You Thousands
When your car starts running hot or you notice puddles under it, coolant leaks, a failure in the system that circulates fluid to keep your engine at the right temperature. Also known as radiator leaks, it’s one of the most common—and dangerous—issues car owners ignore until it’s too late. Coolant isn’t just water. It’s a mix of antifreeze and chemicals designed to absorb heat and prevent freezing. When it escapes, your engine can overheat in minutes, warping parts, blowing head gaskets, or even seizing. This isn’t a "maybe fix it later" problem. It’s a "do something now" emergency.
Most coolant leaks come from a few simple places: cracked hoses, worn radiator caps, failing water pumps, or a damaged radiator. You don’t need a mechanic to spot them. Look for green, orange, or pink fluid under your car after it’s been parked. Smell sweet? That’s coolant. Check the hoses for bulges or cracks—especially near clamps. A loose or brittle cap can let pressure out, causing the system to boil over. And if your engine temperature gauge is climbing even when you’re not stuck in traffic, that’s your body telling you something’s wrong.
The radiator, the main heat exchanger that cools the circulating fluid is often the culprit, especially in older cars. Rust, road debris, or old coolant turning acidic can eat through it from the inside. Then there’s the coolant hose, the flexible tubes that connect the radiator to the engine. They don’t last forever. After 5-7 years, rubber hardens, cracks, and starts weeping. And don’t forget the water pump, the component that pushes coolant through the system. A failing seal here can leak slowly, making it easy to miss—until your engine overheats on the motorway.
Ignoring a coolant leak doesn’t just mean a tow truck bill. It means potential engine replacement. A new radiator costs a few hundred. A blown head gasket? That’s over a grand. And if the engine seizes? You’re looking at a new car. The good news? Most leaks are easy to catch early. Keep an eye on your coolant level every few weeks. Check the reservoir when the engine is cold. If it’s dropping fast, something’s leaking. Smell coolant inside the cabin? That’s often a heater core leak—a sign you need to act before your car turns into a sauna.
What you’ll find below isn’t theory. It’s real fixes from real UK drivers who’ve been there. We’ve pulled together posts that show you how to spot coolant leaks before they destroy your engine, how to tell if your radiator is failing, and why ignoring a small drip can cost you more than a full service. You’ll learn what to check yourself, what needs a pro, and how to avoid being stranded with a dead engine. No fluff. Just what works.
