Noticing strange symptoms like orange fluid under your car or a high temperature gauge reading?
These might indicate your vehicle needs a coolant flush.
But how do you know for sure?
In this article, we’ll explore seven common signs that indicate your vehicle may need a coolant flush, so you can address the issue before it leads to serious damage. We’ll also cover how often a coolant flush should be done and what can happen if it’s neglected.
This Article Includes:
- What Is a Coolant and Why Is a Coolant Flush Needed?
- 7 Tell-Tale Signs You Need a Coolant Flush
- How Often Should You Perform a Coolant Flush?
- What Happens If You Ignore the Signs?
- How to Perform a Coolant Flush: A General Know-How
- 3 FAQs About Coolant Flush
What Is a Coolant and Why Is a Coolant Flush Needed?
Coolant, or the radiator fluid, is a water and antifreeze mixture, usually in a 50:50 ratio. It prevents engine overheating by absorbing heat generated from fuel combustion.
Additionally, coolant fluid contains additives that prevent rust and other forms of corrosion. However, these additives break down over time, leaving the coolant system vulnerable to corrosion.
That’s why it’s best to include regular coolant flushes in your car’s preventive maintenance routine.
But what is a coolant flush?
A coolant flush or radiator flush involves a mechanic draining out contaminated coolant, cleaning the cooling system, and refilling it with fresh coolant. This process prevents engine overheating and other damage caused by dirty coolant.
Luckily, your vehicle will show signs of old coolant long before severe damage occurs.
7 Tell-Tale Signs You Need a Coolant Flush
Here are the common indications that it’s time to get a radiator flush:
- Dashboard warning: Contaminants in the coolant restrict its ability to absorb or release heat, leading to high engine temperature. When the sensor measuring the engine coolant temperature detects this, it triggers a warning on the dashboard.
- Unusual temperature gauge readings: When the coolant is contaminated, the temperature gauge will show unusual readings. For example, a low temperature reading could point to a partially submerged sensor. Likewise, a high temperature gauge reading may indicate low heat transfer.
- Orange or blue-colored puddle under the vehicle: Coolant that has rust and other contaminants can clog the cooling system, causing pressure build-up and coolant leaks. These leaks have a sweet smell (because of the ethylene glycol in antifreeze) and are usually bright-colored.
- Low coolant levels: As mentioned above, the contaminated coolant blocks the vehicle’s cooling system. When this happens, the coolant won’t flow properly, and the sensor will detect low coolant levels.
- Noise from the hood: Low coolant levels can trap air in the vehicle’s cooling system. When this trapped air expands and contracts due to heat, it may produce a gurgling noise.
- Brown or rust-filled coolant: Over time, the additives in the coolant break down and trigger rust formation and other types of corrosion in the cooling system. The radiator fluid accumulates these rust particles and turns brown in appearance.
- Malfunctioning heater: Your vehicle’s heating system relies on the heat carried by the coolant from the engine to warm the cabin. However, contaminated coolant can’t absorb or release heat effectively, leading to poor cabin heating. Additionally, rust and debris in the coolant may clog the heater core, blocking coolant flow and reducing heat transfer.
However, don’t wait for these signs to get a radiator flush. Follow the preventive maintenance routine to avoid low coolant levels, leaks, and other cooling system issues.
That may make you wonder:
How Often Should You Perform a Coolant Flush?
The frequency of radiator flush depends on various factors, including the make of your vehicle and the coolant you use.
Here are the typical flush intervals for different coolant types:
- IAT (inorganic acid technology) coolant: A radiator fluid containing silicates, such as anti-corrosive agents, should be replaced every 2 years or 30,000 miles.
- HOAT (hybrid organic acid technology) coolant: A coolant with organic and inorganic anti-corrosive agents should be flushed every 5 years or 100,000 miles.
- OAT (organic acid technology) coolant: This radiator fluid contains only organic anti-corrosive agents and should be flushed every 10 years or 150,000 miles.
If your vehicle shows signs of dirty coolant before these timelines, you’ll need to perform the radiator flush sooner.
Think it can wait? Here’s why that can be a bad idea:
What Happens If You Ignore the Signs?
Overlooking signs that your vehicle needs a radiator flush can lead to:
- Engine damage: Components of your engine, like the cylinder head and gasket, could rust or get damaged, causing the engine to stop working.
- Cooling system damage: Parts of your car’s cooling system, including the radiator hose and water pump, can cause coolant loss due to clogging from rust and producing too much heat.
- Heater failure: Your vehicle heater will blow out cool air.
- Costly repairs: Fixing the engine, cooling system leaks, and a heater failure individually will cost more than flushing the radiator fluid.
Clearly, regular coolant flushes are essential for your vehicle’s health. Now, let’s see how a coolant flush is done.
How to Perform a Coolant Flush: A General Know-How
A coolant flush involves handling dirty coolant and working with complex engine components. So, it’s a good idea to rely on an experienced mechanic to perform the coolant flush.
Here’s how your mechanic will go about it:
- Place an oil pan beneath the radiator, open the drain valve, and collect all contaminated coolant. They’ll then close the drain valve.
- Open the radiator cap and fill it with distilled water until it reaches the mouth of the opening. They may use a radiator cleaner along with distilled water to help remove built-up debris and contaminants from the car’s cooling system.
- After closing the radiator cap, run the engine with the heater on maximum for 10 to 15 minutes. Then, they’ll wait for the engine to cool down.
- Drain the water just like how they got rid of the old coolant, and repeat this process until the discarded water runs clear.
- Refill with new coolant and double-check to prevent low coolant levels. They’ll remove all air bubbles via the bleeder valve and secure the radiator cap.
NOTE: Your mechanic can also perform a radiator flush through the coolant reservoir. The only difference is that they’ll pour both the distilled water and the new coolant directly into the coolant reservoir instead of the radiator.
Have more doubts?
We’ll clear them next in the FAQs section.
3 FAQs About Coolant Flush
Here are some common questions vehicle owners ask about a coolant flush:
1. How to Determine If You Need a Coolant Flush or Refill
A coolant refill simply means topping off the fluid to the proper level in the radiator. You need to do this when your vehicle shows low coolant levels.
However, if your radiator fluid appears dirty or the vehicle persistently shows low coolant levels even after refilling, it’s a good idea to get a radiator flush.
2. How to Choose the Right Radiator Fluid for Your Vehicle
While selecting your vehicle’s coolant, consider these factors:
- Climate: Ensure your radiator fluid is suitable for your climate. For example, if you live in cold weather, choose an engine coolant with a low freezing point.
- Engine type: While many older vehicles use inorganic, ethylene glycol-based coolants, newer models often require organic acid or hybrid formulations designed for modern engines. Always check your owner’s manual to use the correct coolant type.
- Driving habits: Whether you go on frequent long trips or hardly use vehicles, choose a coolant that suits your driving habits.
- Budget: Some coolants, like ethylene glycol-based OAT, are more expensive than ethylene glycol-based IAT coolants. Choose one that suits your vehicle and your pocket.
3. How Much Does a Coolant Flush Cost?
A professional coolant flush can cost around $140 to $250. This estimate includes:
- Fresh coolant: $10 to $40
- Additives: $15 to $20
- Radiator cleaner: $15 to $20
- Labor: $100 to $170
Let the Experts Handle Your Coolant Flush
Dirty radiator fluid not only damages your engine but also reduces fuel efficiency and harms the cooling system. The longer you delay a coolant flush, the more severe the consequences will be.
If the delay is simply getting your vehicle to a mechanic — we’ve got you covered.
At AutoNation Mobile Service, we come to you, whether you’re at home or the office.
We offer mobile auto repair and maintenance services seven days a week — whether it’s an oil change, a water pump replacement, or fixing a coolant leak.
The best part?
Every repair comes with a 12-month, 12,000-mile warranty for your peace of mind.
Book your slot today to flush out all cooling system troubles.