Hello everyone. I'm new to forums, so I'm not sure if I'm doing this correctly.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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Does anyone know the best way to flush the whole coolant system on a 2001 Chevy Tahoe LS with a 5.3 V8 engine?<o></o>
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I've been having issue with the heater core getting clogged every couple weeks and the heater blowing cold air. I'm pretty sure it is due to the Dex-Cool. I would normally reverse flush the heater core with water or air and that fixes the heat, but only for 2 to 4 weeks and I lose heat again. I'm thinking if I remove the Dex-cool and only use the Prestone Any Make Antifreeze, it may fix the problem permanently.

 

There is a lot of info on "Dex Cool" on here. None good. My 02 cavalier looked like it had kitty litter in the radiator and heater core when i reverse flushed it. Are you sure your not getting gunk from the radiator stuck in the heater core? I had to replace the radiator. Poured CLR in my core to soak for an hour, back flushed and saved the core. Should have done the radiator also while it was out of the car.

 

You may have to replace the core. There is nothing wrong with Dex Cool. The problem comes from the owner not taking care of the cooling system as they should.

 

Thanks for the help. I drained most of the coolant, but I had difficulty removing the engine block coolant drain plugs, so I had to have a local shop finish the job. Only time will tell if changing the coolant worked. If not, I will try the CLR on the heater core. It's worth a try if keeps me from having to replace the heater core. Thanks again.