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Doing a 1800m round trip road trip in a couple weeks (to Laguna Seca Historics, Corvette is the featured Marque this year) and thought its a good time to flush the cooling system. Bought the car in 2011 and have no idea when it was last done. I know my E36 M3 is a bear to get the cooling system free of air, no nothing about the Vette.
Have two gallons of Dex-Cool, 2 gallons of distilled water and one bottle of Water Wetter.
Any DIYs out there? Anything to look out for? Or is it just drain, fill with with water, run for 5 min, drain, fill with the mix of good stuff.
2020 Corvette of the Year Finalist (performance mods)
C5 of Year Winner (performance mods) 2019
the first time I did this on mine I drained the radiator until it stopped then started the car and once it warms up the rest will drain out of the radiator... just keep an eye on the temp gauge and you should have no probs doing that... then I filled with a 50/50 mix of dexcool/distilled water... when filling it just leave the cap off of the surge tank and run the car up to operating temp with the heater on full blast and let the fans cycle a few times and that should remove any air pockets and you're good to go... I remember my trans am had a hex plug on the side of the block behind the starter that you could drain the coolant from the block so that may be another option
When you drain the cooling system on the C5 more than half the coolant stays in the block and there are no drain ***** on the block to get the remaining coolant out. System holds about 13 quarts and draining even with removing hoses only gets 5 to 6 quarts out. Not a lot of fun trying to get ALL the old coolant out. The procedure I used took all day and the next time I will go to a shop that can push out all the old with new coolant and water mix. Costs a few bucks but much faster than draining what you can, refilling with distilled water, running the car to mis the coolant and water, letting the car cool down, then draining and repeating the process until you have nearly all water coming out on the drain......
Good luck with your efforts.
To get the fluid out of the block...
Follow the question mark shaped hose on the bottom of the
overflow tank to the block