Why Your Cooling System Matters: Preventing Car Overheating in Marion, IL

Shawn Miskelley
Jul 16
5 min read

Overheating car coolant issues route 13 Marion IL

It’s every driver’s worst summertime nightmare: you’re cruising down Route 13 when suddenly, steam starts pouring from under your hood, your temperature gauge spikes, and you are stranded on the side of the road. You’ve just experienced the frustrating—and often costly—consequences of car overheating.

At PMR Automotive, we’ve seen it all. From cracked radiators to corroded thermostats, overheating issues are some very common problems we repair at our auto shop in Marion, IL.

So, what causes a car to overheat? Most often, it comes down to one critical system: your cooling system. Let’s take a deep dive into how it works, what can go wrong, and how to keep your car cool—no matter how high the temps rise in Southern Illinois.

What Is Your Car’s Cooling System?

Your vehicle’s engine generates a lot of heat while running. Without a way to manage this heat, your engine would quickly overheat and suffer serious internal damage. That’s where your cooling system comes in—it circulates coolant (also called antifreeze) through the engine to absorb and dissipate heat.

Here are the main components of the cooling system and what they do:

Radiator

The radiator is the large metal board at the front of your vehicle behind the bumper. After coolant absorbs heat from the engine, it flows through the radiator, where air cools it down before it recirculates. The radiator uses outside air, especially the air that passes through the grill while driving, to help cool the coolant down.

Thermostat

This small valve regulates when coolant flows through the engine. When the engine is cold, the thermostat stays closed, allowing the engine time to heat up to optimal operating temperature. As the engine heats up, it opens to allow coolant flow through and cool everything back down.

Water Pump

The pump keeps coolant moving through the system. Think of it like a heart - it keeps pumping the coolant (blood) through the engine (body) to keep it regulated. If it fails, the fluid can’t circulate—and overheating is almost guaranteed.

Hoses

Rubber hoses connect all the components. Over time, these can crack, leak, break down, or swell under the regular pressure and heat.

Heater Core

This small radiator-like device provides warm air inside the car. It's often located within the dashboard to allow air to flow over it and distribute heat into the cab. It’s connected to the cooling system and can affect how heat is regulated inside the engine, too.

Radiator Cooling Fans

These kick on when the radiator needs extra airflow—especially when your car is idling or driving at low speeds.

How Coolant Works—and Why It Needs Maintenance

Coolant is a mixture of water and chemicals (usually ethylene glycol) designed to:

Absorb engine heat
Prevent freezing in winter and boiling in summer
Inhibit rust, scale, and corrosion inside the system

But here’s the catch: Over time, coolant breaks down. The protective additives wear out, and the fluid can become acidic, leading to:

Corrosion inside the radiator and heater core
Scale buildup that clogs passages
Ineffective heat transfer

That’s why most manufacturers recommend a coolant flush every 30,000 to 60,000 miles, depending on the type of coolant and your driving conditions. When you come in for a service at PMR Automotive in Marion, IL, we run a coolant test to check the acidity of your coolant, verifying whether it is still within optimal operation range.

What Happens When a Car Overheats?

An overheated engine isn’t just inconvenient—it’s potentially catastrophic. If your cooling system fails, temperatures under the hood can climb past 250°F within minutes.

Here’s just a few things can happen if you keep driving an overheating vehicle:

🚨 Warped or Cracked Cylinder Head

Heat distorts the metal, leading to compression issues, oil leaks, or complete engine failure.

🚨 Blown Head Gasket

A costly repair that can cause white smoke, oil mixing with coolant, and total loss of engine power.

🚨 Piston and Cylinder Damage

When engine components expand too much due to heat, they can seize or crack.

🚨 Transmission Damage

Some vehicles route transmission fluid through the radiator—if the radiator overheats, so does your transmission.

In short: don’t ignore the signs of overheating. The longer you wait, the more expensive it gets.

Common Signs Your Cooling System Needs Attention

Wondering whether your cooling system is due for a check-up? Here are red flags you shouldn’t ignore:

🚗 Temperature gauge regularly runs hot
💨 Steam or smoke coming from the hood
💧 Puddles of green, orange, or pink fluid under your vehicle
🧊 Heater stops blowing warm air
⚠️ Dashboard warning light for temperature or coolant

Even if your car isn’t currently overheating, any of these signs point to cooling system trouble.

What to Do if Your Car Overheats

If your temperature gauge spikes or you see steam coming from under the hood, follow these steps:

Pull over safely and turn off the engine.
Pop the hood carefully to allow heat to escape (don’t open the radiator cap—it’s under pressure and can cause burns). ONLY DO THIS if you are in a safe space and you feel confident doing so.
Wait at least 30 minutes for the engine to cool.
Call for help. At PMR Automotive, we offer towing for situations just like that. When overheating, it's almost always safest to call for a tow than risk your vehicle overheating more to get to your destination.

How PMR Automotive Keeps Marion Cool

At PMR Automotive, we’re more than just a repair shop—we’re your partners in car care. Our team has the diagnostic tools, experience, and training to keep your engine running at the perfect temperature year-round.

Here’s how we help prevent car overheating in Marion, IL:

✅ Complete cooling system inspections

✅ Radiator repair and replacement

✅ Coolant flush and refill

✅ Thermostat and water pump services

✅ Hose replacements

✅ Fan and heater core diagnostics

We work on everything from daily gas drivers to diesel trucks and electric vehicles. Whether you’re commuting through Marion or planning a summer road trip, we’ll make sure your cooling system is up to the task.

Your car’s cooling system is like your body’s ability to sweat—when it stops working, you’re in trouble. But with regular maintenance and early intervention, car overheating doesn’t have to ruin your plans—or your engine.

If you notice anything unusual, or it’s simply been a while since your last check-up, bring your vehicle to PMR Automotive, your go-to mechanic in Marion, IL.