Don’t Forget to Flush! A Step by Step Guide to a Car Coolant Flush

A healthy coolant system is so important for your car’s engine performance. Don’t forget to flush! Here’s a step by step guide to a car coolant flush.

During Coolant Flush Drain Image

When is the last time you performed a coolant flush on your car’s radiator?

If you’re scratching your head right now and drawing a blank, that probably means that it’s been too long since you’ve had it done. Experts recommend flushing the coolant in your car and replacing it with new coolant every 30,000 miles or 3 years, depending on which comes first.

If you forget to perform a radiator flush or just choose not to do it, it can lead to your engine overheating. You could be left to deal with very expensive car repairs as a result of it.

The good news is that you can keep your engine cool by conducting a coolant flush on your own. Even if you’re not super knowledgeable about cars, it’s easy enough to replace your old coolant with a fresh supply.

Here’s a step-by-step guide to a car coolant flush.

Step 1: Prepare Your Car for Your Coolant Flush

Before you begin performing a coolant flush, you need to park your car on a level surface and let it sit for about half an hour to allow the engine and radiator to cool off. You also need to gather a few items for the flush. Get your hands on:

Outside of preparing your workspace, you should also remove any kids or pets from the area. Coolant, which is often green, orange, yellow, or red, might look harmless, but it’s toxic.

Step 2: Drain the Old Coolant From Your Car

Once you’ve made the necessary preparations for your coolant flush, you’ll be ready to drain the old coolant from your car.

To start, pop the hood on your car and find your radiator fill cap, which is more often than not located right on top of your radiator. Open the radiator fill cap up, and if your car has a plastic reservoir that holds extra coolant, open the cap on that up, too.

Then, climb underneath your car and look for the drain for your radiator. It should be positioned right underneath where your radiator fill cap is. But if you have a hard time finding it, consult the owner’s manual for your vehicle to see exactly where it is (it may be referred to as a “petcock” as opposed to a drain in the manual).

Place the container that you’re going to use to catch your old coolant under the drain and slowly open the drain up to let the coolant in your radiator out. Leave the drain open until there is no more coolant coming out, at which time you can close the drain back up.

Step 3: Pour a Radiator Flush Product Into Your Car

After the old coolant from your car has drained completely, it’ll be time to perform your radiator flush. Use a product like Irontite Thoro-Flush to get the job done.

Thoro-Flush is capable of cleaning your entire cooling system in a single flush. It can clear out gelled coolant from your system and improve both the flow of your coolant and your engine’s temperature control.

Be sure to read and follow the instructions on the bottle. Since Thoro-Flush is a powder concentrate you’ll want to pre-mix it with a little water first. An old plastic milk jug works nicely for this.

Pour Thoro-Flush and one gallon of water into your radiator—not your plastic reservoir—and close the caps on both the radiator and the reservoir.

Step 4: Start Your Car’s Engine

At this point, you should have the old coolant that was in your radiator out of your car. You should also have a radiator flush product like Thoro-Flush sitting in your radiator.

The next step will be to turn your car on and let it run for approximately 10 minutes after the temperature gauge gets into the “normal” range. Do not run it any longer than 20 minutes with Thoro-Flush in your cooling system, as it could cause serious complications with your car. Set an alarm for yourself if you need to so that you don’t lose track of time and allow your car to run for too long.

After the time is up, turn your car off and allow it to sit for a little while until both the engine and the radiator are cool to the touch.

Step 5: Drain Your Car’s Radiator Again

Once your car’s engine and radiator have cooled down, take off the radiator and reservoir caps. Climb back under your car, open your radiator drain, and drain your radiator for a second time.

When the radiator finishes draining, close the drain back up and fill your cooling system with water. Close the radiator and reservoir caps back up and run your engine for a second time for about 10 minutes. Then turn it off giving your engine and radiator a chance to cool down again.

After that’s done, you’ll want to go back under the hood and remove the radiator and reservoir caps one more time and open up the radiator drain under your car.

This will be the final time you’ll need to drain your radiator. When you’re finished, you can close up the container you used to catch your old coolant and set it aside until you can take it to your local recycling center.

Step 6: Refill Your Radiator With New Coolant

Now that you’ve conducted a full coolant flush on your car, you can refill your radiator with new coolant.

The easiest way to do this is by buying pre-diluted coolant that you can pour right into your radiator without worrying about diluting it. Otherwise, you’ll need to dilute full-strength coolant on your own so that it’s a 50/50 mix of coolant and water.

After you pour coolant into your radiator, start your car without putting the radiator cap back on. You should see your cooling system start to bubble before your coolant level begins to rise. That’ll be your cue to replace your radiator cap and tighten it.

Step 7: Check Your Coolant Level

If everything went according to plan, the coolant level in both your radiator and your reservoir should be “full.” If it’s not, you will need to add more coolant to your car. It would be a good idea to refer to your cars owners manual for instruction if needed.

To ensure against any future coolant leaks you could add Irontite All Weather Seal to your cooling system at this time.

You should also come back in a day or two to check the coolant level again. This will ensure you have enough new coolant in your car to carry you for at least another 30,000 miles or 3 years. 

Perform a Coolant Flush Today

When you own a car, there is so much maintenance that you’ll need to do to it. It can be overwhelming for some people and can cause them to overlook obvious maintenance steps they should be taking.

Don’t allow that to happen when it comes to conducting a coolant flush. Make sure you perform a flush on your radiator every few years to get the best possible performance out of your engine.

Contact us today to get more information on Irontite Thoro-Flush and all of the other Irontite products.