How to do a coolant flush

How to do a coolant flush yourself

It’s easy to do a coolant drain and refill on late model cars, but it’s not so easy to do a coolant flush yourself

There’s only one way to do a coolant flush at home yourself and it’s not cheap nor easy

First, it’s often not even possible to connect a cooling flush kit to late model vehicles

On older vehicles, carmakers used rubber heater hoses to carry coolant from the engine to the heater core. On those vehicles it’s easy to tap into the heater core inlet hose to install a flushing Tee so you can back-flush the cooling system.

But most late model engines use steel tubing with short sections of rubber tubing that aren’t large enough to accommodate a flushing tee, making it almost impossible to perform a home cooling flush.

Coolant flushing and street draining isn’t legal and it’s not safe

In the old days, you’d connect the garden hose to the flushing tee, turn on the water and all the old coolant would flow out of the radiator, onto the ground and down into the storm sewer. Draining coolant into the storm sewer is now illegal. Even if you ignore the legal issues, it’s just not a good idea. Coolant contains toxic ingredients and winds up in our lakes and streams. It kills wildlife and fish.

Tap water isn’t good for your engine

Pre-mixed coolant contains de-ionized water, which is best for your engine. Tap water from your hose contains minerals which are not good for your engine.

To legally and safely flush your cooling system yourself, you’ll have to catch and recycle all the old coolant and use a pump to inject the distilled water

The Prestone cooling system flushing kit comes with a Tee, hose adapter, cap, hose clamps and a radiator spout.

To install the kit you’ll need:
• Electric pump with garden hose adapters
• Hose shut-off clamps (or drain the system first)
• Screwdriver
• Knife
• Several gallons of distilled water

1) Locate the heater core inlet hose
2) Clamp off two sections of the inlet hose.
3) Cut out a section of the inlet hose and install the flushing tee with hose clamps
4) Attach the garden hose adapter
5) Connect a garden hose to the adapter and the other end to the pump
6) Raise the vehicle and place a large drain pan under the radiator or coolant reservoir to catch all the old coolant
5) Remove the radiator cap and install the radiator spout
6) Pour the distilled water into a bucket and dip the pump supply hose into the bucket
7) Turn on the pump and backflush the cooling system using distilled water. Pump until the drain water from the radiator is clear
8) Calculate how much coolant concentrate to pump back into the system to get a 50/50 mix.  Then run the pump to pump in all the coolant
9) Bottle up all the old coolant and take it to a recycling center

If you’re not up for a full coolant flush, here’s how to do a coolant drain and refill

©, 2016 Rick Muscoplat