What Happens During a Coolant Flush

Cooling System

You may not always know when your car needs a coolant flush until it’s too late. By that time you may be pulled over on the side of the road with steam shooting out of your hood. Fortunately, with a simple coolant flush you can make sure that this problem never happens to you. Even though you know that this is an important aspect of car ownership, you may not know why it’s important or exactly what goes on during a coolant flush. In this article, we’ll give you a little insight into what exactly is going on with your car during a thorough coolant flush and hopefully demystify this important systems maintenance step for your car or truck.

The Optional Pressure Test

If there is a suspected leak in your coolant line then one thing that will likely be done before any flush happens is the pressure test. The pressure test involves a piece of equipment that looks, and acts, a lot like a bike tire pump. It will pressurize your coolant system and, if the pressure begins to quickly drop, it will indicate where a leak is located. If you haven’t noticed a leak in your car or there is no leak in your cooling system then it will be time to flush out your cooling system.

Flushing Your System


The first thing that your auto mechanic will do is drain your coolant from your system. Ideally, if you’re keeping up with your maintenance, your coolant should come out slightly darker than when it went in, but not much. Your mechanic will take that old coolant and recycle it, just like they do with the dirty oil that they collect from vehicles as well.


Next, your car care specialist will insert a washer near various key points of your vehicle’s cooling system to flush any dirt and debris from your system. They will usually start with your radiator itself and allow it to all drain out. After they will drain the system once more. Then they will wash out the area near the water pump, where there are a lot of little seals that, if cracked, can cause leaks and add even more debris to your cooling system. After another drain, your mechanic will wash out the heater core. Again, this ensures that no debris are hiding out in places that your coolant will usually collect or deposit debris.

With many radiator flushes, if the system isn’t cleaned out thoroughly, there will still be a significant amount of debris left inside of the system, which could cause further damage or even negate the point of the coolant flush. After one last drain of your cooling system, your Golden Triangle Auto Care ASE certified technician will fill up your vehicle with the correct coolant and you should be ready to go without any worries about your coolant system.

The next time you need a coolant flush, visit Golden Triangle Auto Care at 1112 North Speer Blvd. or call us at (303) 573-1335.

Contact Golden Triangle Auto Care





1112 North Speer Boulevard
Denver, CO 80204

Store Hours:

M-F: Open 7:30 am Close 5:00 pm
Sat: Closed
Sun: Closed

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