Top 5 Cooling System Maintenance Myths Busted

Add amateur mechanics and unethical auto repair shops to the already confusing conversation, and it’s tough to get a straight answer.

Not only could this result in you paying for unnecessary services, the wrong recommendation could cause extensive damage to your vehicle. That’s why Christian Brothers Automotive wants to set the record straight.

Last week, we explained how your car’s cooling system works and why it’s such an essential part of your vehicle’s operation. This week is the second installment in the Christian Brothers Automotive series on cooling system maintenance and repair.

We’ll correct 5 cooling system misconceptions and tell you the truth about your car.

Cooling System Myth #1: This system doesn’t need service

One common misconception is that the cooling system is a maintenance-free system. In certain vehicles, when coolant breaks down, it may cause rust and rust particles to become electrically charged. When this happens, the coolant can become highly corrosive. This can result in major damage to the engine and cooling system.

Others believe a vehicle’s coolant does not need to be flushed, but simply topped off. Similar to a car’s oil, coolant breaks down over time. If not serviced, old or broken-down coolant can wear down the engine or cause corrosion.

Cooling System Myth #2: A small coolant drip isn’t a big deal

A small bit of fluid on the garage floor may not seem important, but it’s a big deal. First, it’s against both state and federal laws to dump antifreeze and other hazardous substances into surface waters.

When you park your car on the street, that’s exactly what you’re doing. Rainwater washes the coolant into the storm drain, which then dumps these dangerous substances into your community’s water supply.

Second, glycol (or antifreeze) is very poisonous. It has a sweet taste that dogs and small children find irresistible. Letting it out of your car – one way or another – is a recipe for disaster. In addition to the health and environmental hazards, a leaking radiator will lead to cooling system failure.

If the radiator itself has a leak, the radiator will eventually split open and dump all remaining coolant. If the leak is in a hose, the hose will blow out. In other words, all kinds of nasty things can happen that will end up costing a lot more time and money than fixing a small leak when it’s first noticed.

Cooling System Myth #3: When your car is overheating, you should slow down

When a driver notices their car overheating, the first instinct is to pull over and turn off the engine. This is the wrong choice. Engine cooling is a combination of coolant flow and airflow across the radiator.

What should you do instead? Sometimes, the best solution is to increase vehicle speed (or engine speed) to provide more coolant flow, more airflow or both. Another trick is to turn your heater on full-blast.

This works because the heater is basically a cooling coil that dumps heat from the engine inside the cabin of the vehicle. If it’s hot outside, you will be uncomfortable. But, you’ll save the engine.

Cooling System Myth #4: All anti-freeze products are the same

While many auto mechanics wish this myth were true, it’s not. In fact, some car manufacturers will void the car warranty if you don’t use the specified fluid. Be sure to check your vehicle owner’s guide before you pour any old product into the cooling system. Like your oil, antifreeze is a vital fluid and it needs to be filled to the correct specification.

Likewise, many believe 100% antifreeze is necessary. Actually, straight antifreeze will freeze when the temperature drops low enough. While it may sound counter-intuitive, mixing the antifreeze with water lowers the risk of your coolant freezing in the winter.

Cooling System Myth #5: All you need to do is keep the coolant full

Many drivers are under the impression the coolant level is the only important factor. In actuality, the quality of the coolant is just as important. As we’ve already mentioned, your coolant will break down just like the motor oil or any other fluid in your vehicle. Because of this, it’s essential to perform periodic coolant flushes.

If you’re receiving a service that removes all the coolant (like a water pump replacement), it’s natural to think, “All the coolant is out, why do I need a coolant flush?” But a flush does more than simply remove the fluid. During a flush, the built-up contaminants in the system are also removed.

All the scale deposits, rust and particulates are thoroughly cleaned out and the entire system is scrubbed down with a detergent and protective conditioner. Keeping your cooling system well-maintained and full of high-quality coolant will protect your car against corrosion and future damage.


Your cooling system is made up of multiple parts, including belts, hoses, fittings, and coolant.

Accessory Belt: One belt, many problems

To reduce overall space and weight in the engine compartment, today’s engines use a single plane design accessory belt to drive the A/C compressor, Water Pump and Alternator.

In terms of engine failure, the cooling system’s water pump is the most important component that is highly dependent on the condition of the belt and the condition of the accessories the belt drives. If any of the accessories cause the belt to wear out, your engine’s cooling system may fail catastrophically.

Keeping a close eye on the accessories belt and the accessories it runs will help prevent indirect cooling failures.

Hoses: They may look good…on the outside

The cooling system’s hoses are made of a firm but flexible rubber, which allows water to pass through the cooling system components. Mostly, they’re designed to flex and absorb the engine’s vibration. Over time, the hoses develop problems that can’t always be seen on the outside.

A common problem is the hardening of the hose’s inner wall, which degrades the flexibility of the hose design so it can no longer dampen the engine’s vibration. Other problems like leaks, metal corrosion and stress cracks at the connection ports of engine, radiator, and heater usually lead to costly repairs that may have been preventable with proper maintenance.

Fluid: Not all coolant is created equal

Cooling systems are designed to work under pressure. Periodic visual fluid level checks can quickly determine if there’s a concern for leaks. You should always consult with a professional before opening the system. There’s always a potential of harmful fluid eruption, even if you think the temperature is safe.

Engines (and the parts of the cooling system) are made of different metals that are designed to work with specific fluid types and mixtures to prevent metal corrosion, catastrophic engine failure and the production of harmful environmental byproducts.

The periodic testing and inspection of fluid type, quality and level can be done by our ASE-certified technicians during a Courtesy Inspection.

When Should Cooling System Service Be Scheduled?

It is good practice to inspect your engine’s cooling system parts with every oil change, however the cooling system fluid only needs to be checked to ensure it is at the proper level and condition and no potential leaks are suspected.

Because of the manufacture’s specific cooling system fluid design, always check the manufacturer’s recommendations by mileage and/or condition of fluid. In most cases, you should only require full cooling system service (with related component maintenance) every 3-5 years.

Your cooling system is a complex part of the vehicle’s function

With the right information, you can protect your vehicle and help your car drive stronger for longer.

If you have any questions about the cooling system or are in need of an inspection, call your local Christian Brothers Automotive. You’re sure to see the nice difference!