Best way to do a complete coolant flush?
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TECH Senior Member
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Joined: Nov 2001
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From: Lexington, Ky
Best way to do a complete coolant flush? Since my car has a 160*F thermostat it turned my coolant brownish-black with a bit of a granular appearance. What's the best way to flush out the ENTIRE coolant system to rid it of this? I'll put in a warmer thermostat, too, to correct this. My 2 brother's LS1's did the same thing to their coolant when they had 160*F.
Re: Best way to do a complete coolant flush? WE use a Wynn's flush machine at work,it does a great job. Turn the heat on through the floor vent to involve the heater core. If you still have Dexcool as your coolant there is a TSB from GM that addresses the condition you speak of and it states in general that if the vehicle is driven for a period of time with the cooling system not completely full you will see the discoloration that you speak of, the resevour can also look like "mud" has acumulated in it. If I remember correctly it does not diminish effectivness.
Re: Best way to do a complete coolant flush? I forgot to ask if you are finding the grandular material just in the resevouir and on the bottom of the radiator cap or actually in the radiator itself?
