AutoZone How-To: Flushing and Filling Your Cooling System

Your car's cooling system is the number one reason for engine-related breakdowns on the road. Learn how to properly flush and fill your cooling system regularly, and protect your engine, with this helpful guide. You can find everything you need for the job at your nearest AutoZone.

[ronhenson]

Years ago my father used a "flushing agent" by a leading brand manufacturer before we went on a trip out of state. Some of the "flushing agent" was still in the system as we traveled maybe 120 miles. The dummy hot light came on but it was too late, the engine was already burned up. To this day, I have never and will never use a "flushing agent" by any company when doing a drain and refill. My mechanic told me when doing a drain and refill to remove the bottom radiator hose and radiator cap. When all the coolant drains out, turn the ignition key on and off three times to remove additional old coolant in the system. Replace the radiator hose and fill with new coolant while the engine is running and the heat is set to hot and fan speed on high, run for 5-10 minutes. Turn everything off, top off with coolant as needed. Check regularly in the coming days or weeks depending on how much you drive to add coolant as needed. My radiator and overflow are part of my regular checks under the hood. I hope this information saves you from burning up an engine. WEAR SAFETY GLASSES & DISPOSABLE GLOVES WHEN WORKING ON YOUR VEHICLE. PEACE.

[drafter_freedom]

Step one: make sure engine is cool before opening the radiator cap!!!

[Shiznit]

6:09 pulls out funnel to pour in directly, spilling everywhere lol

[TJones-vewd]

What he failed to mention was that there is quite a bit of water left in the engine block even after the radiator is drained. So, when he added a mix of 50/50, what the engine actually ended up with was weaker than that due to the water left in the engine block. The better way to do this is to add half the capacity in straight antifreeze, then top off with distilled water.

[Wongburger]

6:07 the funnel was too helpful, gotta make a mess.

[wonderwalls]

For all the Do it yourself people, this is not a flush this is draining the radiator and filling it after draining. Check your coolant and if its good but you still want to change it for the pece of mind then just empty the radiator and fill it couple of times. no need to fix something which is not broken. I learnt the hard way.

[momoneyinvesting]

Can we see how to do this on a car that isn't from the Civil War?

[brandonb]

Missed a lot of steps and vital information like getting all air bubbles out of the system

[ChilledSon]

Please DON'T DO THIS If you live somewhere like Canada where it gets really cold. Your block could freeze and crack when it's -35 celsius outside.The final mix ratio using this method will not be 50/50 because there is still distilled water in the block and in the loop (or even worse, tap water or some flushing product). Quite a bit of water too! For example, in a 'typical' 4 cylinder sedan the flush volume could be 5.2 litres vs total volume of 6.5 litres. The difference of 1.3 litres is 20 percent of total volume of 6.5 litres. That is enough to significantly change overall ratio. If you your freeze plug doesn't pop out or you live further North where it goes down to -50 celsius : game over.

[siachen]

How do you drain out the distilled water completely from the engine block and heater core and hoses in the cooling system?

[byronwoolfrey]

This is what you get at a garage sometimes. Didn't drain or clean the reservoir. Replaced the stuff with a different kind than the original

[thehegt]

why didn't use the funnel when mixing the 50/50 ? .

[eduardthornton]

Truly appreciate your thoroughly professional video. You know exactly what you're doing and it shows in many ways. I look forward to many of your other videos. You are my trusted source.

[MachAviationt]

Nice video! When you fill in your own fresh 50/50 coolant at the end, will the final ratio still be 50/50 given that there remains to be some distilled water left in the system from your last flush?

[studntselac]

Didn't talk about burping/bleeding the cooling system. What happens if you fill up the reservoir pass the full mark?

[liliankuhn]

When draining it, does it drain all of the coolant from the overflow jug? Not one video explains this.

[Mark-umhm]

I was always told, your car should be running when you add coolant? Is that a myth?

[LabradorRichy]

How about burping the system in the end to get rid of air

[ebw]

What about safety? How long it takes for an engine to cool down depends on the engine size and what it is made from. Aluminum cools off faster than cast iron. Always squeeze the top radiator hose and if there is pressure, don't take the cap off.

[DoseOfRealityShow]

After u insert the flushing product and water do you put back on BOTH the radiator cap and drain plug while running the car witht he heat blasting??