How to Install a Coolant Flush Kit

Last Updated: November 18, 2021 References

It's important to flush out your coolant system every few years. Over time, particles in your antifreeze can clog up your cooling system, leading to overheating and engine damage. Luckily, flushing your radiator and changing your coolant is easy with a flush and fill kit. We'll walk you through the process of doing a coolant flush so you can keep your ride running smoothly.

Part 1

Part 1 of 3:

Tee Attachment and Flush Preparation

1
Check the engine to make sure it is no longer hot. Loosen the radiator cap to release any pressure still left, and then re-tighten.
- Many newer cars have the cap on the coolant reservoir instead of the radiator itself, but, on certain cars, there may be no radiator cap at all. In this case, emit the pressure by loosening the thermostat cap.
2
Place a pan or bucket under the radiator plug beneath the car to catch the old antifreeze. Elevating the car on ramps may help the process.^{[1]
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3
Splice the "Flush Tee" to the heater inlet hose. The heater inlet hose usually runs between the firewall and the top of the radiator. This may be done using a clamp and a couple of screws.^{[2]
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Part 2

Part 2 of 3:

Attach the Coupler and Back Washing

1
Remove the cap covering the tee as well as the radiator cap. Attach a coupler to the flushing tee to prevent backwash.
- The black part should attach to the tee and the yellow part should attach to a garden hose. On cars with no radiator cap (or reservoir cap), flush by disconnecting the upper radiator hose.
2
Flush with tap water until it runs clear. A cleaning solution may have also been provided in the antifreeze flush kit.^{[3]
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Part 3

Part 3 of 3:

Refill

1
Mix antifreeze according to what your climate needs, somewhere between a 50% and 70% mix.
2
Pour the amount you measured into your radiator, reservoir or thermostat opening. Some leakage of water and diluted antifreeze will come out of the tee.^{[4]
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3
Recap the tee and tighten the clamp by hand. Replace your radiator cap and run your car for 10 minutes after it reaches its running temperature.
4
Allow your engine to cool again and check antifreeze levels. Add more as needed.^{[5]
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Community Q&A

Question

How do I flush the engine block?

Rawfoodbreeder

Community Answer

First, open the thermostat housing. There is a bolt attached to the engine block, you're going to have to look for it, where the block meets the oil pan. Look around on the block below the exhausts. When refilling, make sure to flush all the air out of the system.

Warnings

Do not open the radiator cap while engine is hot. A spray of hot antifreeze can severely burn you.

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Dispose of old antifreeze properly. Anti-freeze tastes sweet and can cause severe poisoning or even death if swallowed.^{[6]
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