Heater Core Flush - Chevrolet Impala SS Handbook

5. Put bottom hose back on and remove the top hose near the air box.
6. Start car and let it push the remainder of the coolant out of the system. Using a hose run water into the
overfill container. It will suck it into the motor about as quickly as the garden hose can fill it. Continue
doing this until you see no more coolant come out. You might want to cycle the heat on to get water
through the heating core. It might take a little bit for the thermostat to open but when it does all the old
gunk and coolant comes out. When finished, thoroughly wash off all of the anti-freeze off the front of
your car. That stuff can't be good for the paint.
7. When all the old coolant is gone, stop putting water into the overflow tank. Let the motor pump dry.
When the water starts to surge out of the hose shut her down. You still have about 2 gallons in the system.
8. Put all the hoses back on tightly, and start to fill the overflow container with straight anti-freeze.
Remember there is still 2 gallons of water in the motor.
9. Start motor and let it suck everything in through the overflow. When it won't take anymore and the stat
has opened (top hose will be warm) then open the bleeder valve going into the thermostat. See Bleeding
the System.
10. Put the resonators back in place on the motor, if you are using them, and make sure all hoses are on and
tight. Do not forget the little overflow hose.
11. Keep adding until you are at the cold fill mark and go drive for a few days. Top off some morning to the
cold fill and you are done.
Tools:
Procedure:
1. Put a bucket or pan beneath and slightly ahead of the serpentine belt tensioner. You may have to readjust
the bucket once the draining starts.
2. Disconnect heater core hoses at the water pump. These are the two smaller hoses facing the passenger
side, towards the battery. The lower hose and pipe will dump a bunch of coolant out of the engine into the
bucket. Be sure it doesn't get all over the opti-spark behind the crank damper.
3. Take a garden hose, put it up against the lower hose, and run until it goes clear. Soon people believe that
getting bubbles in the flow will help clean everything out.
4. Now switch to the pipe and back flush.
5. Repeat spraying water into the lower hose until the heater core water runs clear or it hacks up a hairball.
6. Repeat Steps 3-5 a few times to be sure you've cleaned everything out of the system.
7. Reassemble cooling system, fill up the expansion tank and screw the cap on.
8. Bleed the system.
9. At this point, the heater should start getting hot. Repeat until you've replaced all of the coolant you lost.
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BTW - keep the rest of the cooling system closed up when you do this. Do not try to be slick and hook a
hose to your bleeder valve, open the reservoir cap and dump the extra fluid back in. It is self-defeating.
Just open the bleeder valve and put a rag or paper towel next to it; leave it cracked open a turn until
coolant starts coming out, then close it up. Drive around for a few heat cycles, repeat.
Maintenance: Cooling System

Heater Core Flush

SSHandbook
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