Vortec 350 Radiator Flush

[Nick1994]

The truck in my sig below I changed the coolant in February 2011 with 144,000 miles and 50/50 Dexcool and Distilled water. I didn't do a full on flush with the thermostat out, and didn't run the Prestone flush very long. I now have a new thermostat and have been considering a coolant flush. The radiator has a date stamp from 2005 so I think it was changed then. Should I take out the thermostat, drain the coolant and flush with water,and with Prestone flush and drive for a week or so then refill with antifreeze? What's the best with these Vortec 5.7's?

 

[901Memphis]

With the thermostat out you can get all the old coolant out in hours just by adding Distilled water each time you drain the radiator and mixing it. All you need to do is run it a few minutes in between drains. If it's dirty that's another story but it sounds like it's in okay shape.

 

[Chris142]

The flush may remove whatever is holding your intake manifold gasket together.

 

[KenO]

I ran mine with some industrial Cascade with phosphates for about a week to 'clean' it out. Worked great. I mean, if you are pulling the t-stat too, just sue a garden hose and flush the block out. I did that, and then, using a couple shop rags, used compressed air to blow the rest of the water out of the cooling system,a nd the heater core. Amazing the nastiness that came out of the heater core.