Why does the engine overheat: causes and how to fix?

So, your temperature gauge is creeping into the red, or worse—steam is billowing from under the hood. That’s not just an inconvenience; it’s an engine killer. If you keep driving an overheating engine, you’re flirting with a cracked cylinder head, a blown head gasket, or even total engine failure. Translation? A repair bill big enough to make you cry.

Let’s break down why your engine is overheating, what you should do about it, and how to prevent it from happening again.

Find Out Why Your Engine Is Overheating

Engines are designed to run hot, but when they run too hot, something’s wrong. The most common culprit? A cooling system that’s not doing its job.

Cooling System Failures

• Low Coolant Level – Your engine relies on coolant (also called antifreeze) to regulate temperature. If there’s not enough, heat can’t escape, and the temperature skyrockets.
• Coolant Leaks – If your coolant level is dropping but you never see a puddle under the car, it could be leaking internally. A blown head gasket might be letting coolant mix with the oil—bad news.
• Thermostat Stuck Closed – The thermostat controls coolant flow. If it gets stuck shut, coolant never reaches the radiator, and your engine boils over.
• Clogged Radiator – Over time, dirt, rust, and debris can block the radiator’s passages, preventing coolant from flowing properly.
• Broken Water Pump – If the water pump fails, coolant won’t circulate through the engine, and overheating happens fast.

Other Possible Causes

• Radiator Fan Not Working – If the fan isn’t spinning, especially when you’re idling, heat won’t dissipate properly.
• Old or Low Engine Oil – Engine oil lubricates moving parts and helps with heat dissipation. If it’s old, dirty, or low, friction increases, and the engine runs hotter.
• Air in the Cooling System – If air gets trapped in the system, coolant flow gets disrupted, leading to overheating.
• Extreme Driving Conditions – Heavy towing, stop-and-go traffic, or driving in scorching heat can push a weak cooling system over the edge.

How to Spot the Problem

What to Do If Your Engine Overheats

If you’re driving and your temperature gauge spikes, don’t keep going unless you enjoy expensive repairs. Here’s what you should do:

1. Turn off the A/C and turn on the heater. Sounds backward, but it pulls heat away from the engine.
2. Find a safe place to pull over. Do not wait until you see smoke.
3. Turn off the engine immediately. If you keep driving, you’re risking catastrophic damage.
4. Wait at least 30 minutes before checking anything. Hot coolant is under pressure—if you open the radiator cap too soon, you’ll get a face full of boiling liquid.
5. Check the coolant level. If it’s low, add coolant (or water in an emergency). If the reservoir is bone dry, you have a leak.
6. Look for leaks. Check under the car for puddles. If you see green or orange fluid, you’ve got a problem.
7. If the engine is still overheating, call for a tow. Don’t risk blowing the head gasket.

Fix the Problem

Now that you’ve cooled things down, it’s time to get your hands dirty and fix what’s wrong.

Coolant System Fixes

• Low Coolant – Add coolant, but find out why it was low in the first place.
• Leaks – Inspect hoses, the radiator, and the water pump. Replace anything leaking.
• Thermostat Stuck Closed – If your engine overheats fast and stays hot, replace the thermostat.
• Clogged Radiator – If your radiator is clogged with gunk, flush it or replace it.
• Water Pump Failure – If coolant isn’t circulating, you’ll need a new pump.

When to Call a Mechanic

Overheating is a big deal. If you ignore it, you’ll be shopping for a new engine—or a new car. Regular maintenance is the best way to avoid costly repairs. Check your coolant levels, inspect hoses, and don’t ignore small leaks. Stay ahead of the problem, and your engine will thank you.