Tips to Flush a Car Radiator (5 Simple Steps) and Cost Info

Last Updated on May 11, 2019 by themechanic

We don’t commonly think about how hot it can get in an internal combustion engine. There are several metal components in an engine which are moving fast; some even rubbing against each other. All this motion and action generates excessive amounts of heat.

In order to keep the engine cooled down, the components need oil and coolant liquid. Oil assists in reducing the friction and allowing the components to function more smoothly. Coolant fluid absorbs existing heat from the engine and transfers it to the radiator. Once the radiator receives the heated coolant, the radiator sends it out into the air with the help of a fan. All the coolant in the radiator flows back into the engine to absorb more heat again. This cycle keeps repeating as you drive so that your engine never overheats.

5 Steps to Flush a Car Radiator

Like any other liquid in your vehicle, coolant isn’t going to stay fresh forever. You’ll need to eventually flush all the old coolant fluid out of the radiator and replace it with new coolant fluid. But you must know the proper steps to take during this process or else you could mess up your radiator.

To ensure you flush your car’s radiator properly, below are the top 5 tips of this process.

1) 5 Years / 100,000 Miles

First, you must know when the right time to flush your radiator is. If you check the owner’s manual of your vehicle, the manufacturer will give you their recommendation. In most cases, they will recommend that you flush the radiator every 100,000 miles. But if it’s been 5 years and you haven’t reached this mileage yet, you should flush the radiator anyway. Of course, the average auto mechanic may say it’s better to flush every 25,000 or 30,000 miles. But they just want your business, so who can really believe them.

2) Drain the Old Coolant

Once it’s time to flush your radiator, you must first make sure your engine is in a cooled down state. This means that you shouldn’t drive for a minimum of 30 minutes before doing the flush. Now you’ll need to drain the old coolant out of the radiator. Put a pan or container underneath the radiator because you’ll want to catch all the coolant fluid when it comes out.

3) Use Cleaning Solution

After the radiator is drained of all its coolant, pour a radiator cleaning formula into its reservoir. Your local auto store should sell this radiator cleaner. Next, pour some distilled water in there with the formula. Now go to your driver’s seat and turn on the engine. Activate the heater and set it to full. Wait 5 minutes while all the debris, rust, sediment, and other contaminants are cleaned out of the cooling system. Turn off the engine and leave the vehicle for 30 minutes.

4) Drain Cleaning Fluid

Drain the vehicle of the distilled water and radiator cleaning formula. The draining process is the same as before. Use a pan to catch the liquid as it comes out from underneath the radiator. If the water is darker, then it is a sign that the system was cleaned. Once all these fluids are drained out, flush the system one more time with mere tap water. This removes any bits and pieces that may still be in the system.

5) Add More Coolant

Drain out the tap water from the radiator. Finally, you can add the new coolant liquid to the reservoir of the radiator. You’ll want to add 0.5 gallons of distilled water and 0.5 gallons of antifreeze. Verify these measurements in the owner’s manual just to be safe. If you’ve added the coolant, turn on your engine and wait 15 minutes for the coolant to flow through the engine.

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Cost to Flush a Car Radiator

It is not too expensive to flush your radiator of all its coolant. If you went to the average auto shop, they would likely charge between $100 and $200. To get the cheaper end of this range, you need to research the prices at the various auto shops in your local area. The smaller auto shops may charge just $50 to $100 if you’re lucky. Other factors which influence the price are the amount of coolant fluid you need and the make and model of the vehicle. Four gallons should be about what you’ll need.

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