Hi all,
I just picked up 2 gallons of dex cool & 2 gallons of distilled water.
Do I just drain radiator. Fill with tap water get engine warm drain & do that a few times till water is clear then put in the 50/50 mix ???

 

You'll only need one gallon of coolant and one gallon of water. I make a 50/50 mix first and then pour it in my drained system. The level may go down and then all I do is add the premixed stuff. Hope you bought the correct coolant....there are only two brands of Dex-Cool: Texaco (the inventor) and the GM brand, which is made by ChevronTexaco. Don't fall for the "compatible with" brands or "can be mixed with" brands, or other "long-life" brands.

 

I bought the Texaco - Havoline 5 year 150,000 it cost $10 a gallon.

 

Since no one would come to my rescue I did a search on the internet & found the below.


Changing coolant in a LS1 is a little more time consuming than it was with older Corvette engines because the engine block coolant drains are not accessible when the engine is in the car. The left drain is hidden behind the engine mount bracket and the right drain is behind the starter. Because of this you can't fully drain the system; you only can flush it. This work may also involve working with hot engine parts or hot liquid. We suggest you use some automotive work gloves such as "Mechanix Gloves" sold by Mechanix Wear. We like them because they protect hands but still allow good feeling.

The radiator drain is at the lower, right corner of the radiator. Open it, let it run until the flow stops, close the drain and refill the system with water. Run the engine until the thermostat opens, shut off the engine, carefully release the pressure in the cooling system and open the radiator drain again. Repeat this procedure until the coolant coming out of the radiator runs clear. You may need to do this tedious flushing trick several times to get the water to run clear.Once the flushing is done, close the drain and fill the system with a 6.5 qts. of Dex-Cool (50%) and, optionally, a bottle of Red Line SuperCool. Add distilled water until it reaches the base of the surge tank neck. Start the engine and let it idle for a minute then cycle engine speed from idle to 3000 rpm and back until coolant temperature reaches 210¡F. Remove the tank cap, observing the cautions discussed previously. The coolant level should be about 1/2-in. above the "cold full" mark on the tank. If it is not, top off with distilled water, replace the cap, start the engine and repeat the above procedure.

(more about the draining)

Use a ¼” drive extension to insert into the white radiator drain plug. (This plug is located on the passenger side of the vehicle just inside of the A/C line) The plug has course threads and only requires about a ¼ turn to open fully. The fluid will come out the drain highlighted in the picture.



After about a gallon of coolant has drained the flow will slow down considerably. Be patient as this is not enough to start the thermostat removal process yet. You will need to drain at least a gallon and a half to get the coolant level below the thermostat housing. At this point you can close the plug. You will feel it snap or click into place, this lets you know it’s safely closed all the way.

 

It is more expensive ($100) but I'd suggest the power flush, it gets all the old coolant and replaces it with new 50/50. Drain and fill will leave old coolant, sludge, and deposits in the engine.

I did mine at 5 1/2 years and 10k miles

 

I agree - I'd spend a little more and get the system power flushed. Good to know you got all the old stuff out.

 

I change my Dexicool every 50k, so I don't drain the block. I do pull the T-stat and dump the surge tank.